Repository: ross-rotordynamics/ross
Pull request #363 (2019-10-29 19:20:11)

Improve docs
Many changes to the documentations regarding the format.
I had to change some docstrings to add a blank line after each section so that sphinx could render the documentation properly.

codecov-io: # [Codecov](https://codecov.io/gh/ross-rotordynamics/ross/pull/363?src=pr&el=h1) Report
> Merging [#363](https://codecov.io/gh/ross-rotordynamics/ross/pull/363?src=pr&el=desc) into [master](https://codecov.io/gh/ross-rotordynamics/ross/commit/06e6186eb031ea4181db884203a72e02d6fd6ca8?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `96.55%`.

[![Impacted file tree graph](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/graphs/tree.svg?width=650&token=SZjY7TrJnS&height=150&src=pr)](https://codecov.io/gh/ross-rotordynamics/ross/pull/363?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master     #363   +/-   ##
=======================================
  Coverage   73.66%   73.66%           
=======================================
  Files          14       14           
  Lines        3706     3706           
=======================================
  Hits         2730     2730           
  Misses        976      976
```


| [Impacted Files](https://codecov.io/gh/ross-rotordynamics/ross/pull/363?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [ross/element.py](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/diff?src=pr&el=tree#diff-cm9zcy9lbGVtZW50LnB5) | `80.35% <ø> (ø)` | :arrow_up: |
| [ross/shaft\_element.py](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/diff?src=pr&el=tree#diff-cm9zcy9zaGFmdF9lbGVtZW50LnB5) | `88.75% <ø> (ø)` | :arrow_up: |
| [ross/disk\_element.py](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/diff?src=pr&el=tree#diff-cm9zcy9kaXNrX2VsZW1lbnQucHk=) | `96.33% <ø> (ø)` | :arrow_up: |
| [ross/rotor\_assembly.py](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/diff?src=pr&el=tree#diff-cm9zcy9yb3Rvcl9hc3NlbWJseS5weQ==) | `91.32% <100%> (ø)` | :arrow_up: |
| [ross/results.py](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/diff?src=pr&el=tree#diff-cm9zcy9yZXN1bHRzLnB5) | `52.04% <100%> (ø)` | :arrow_up: |
| [ross/utils.py](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/diff?src=pr&el=tree#diff-cm9zcy91dGlscy5weQ==) | `71.03% <100%> (ø)` | :arrow_up: |
| [ross/bearing\_seal\_element.py](https://codecov.io/gh/ross-rotordynamics/ross/pull/363/diff?src=pr&el=tree#diff-cm9zcy9iZWFyaW5nX3NlYWxfZWxlbWVudC5weQ==) | `55.78% <95%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/ross-rotordynamics/ross/pull/363?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/ross-rotordynamics/ross/pull/363?src=pr&el=footer). Last update [06e6186...7d14158](https://codecov.io/gh/ross-rotordynamics/ross/pull/363?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).


Patch:
diff --git a/docs/_static/style.css b/docs/_static/style.css
index 920b2cbb..6d42a0c2 100644
--- a/docs/_static/style.css
+++ b/docs/_static/style.css
@@ -18,3 +18,7 @@ pre {
     border: 1px solid #cccccc
 }
 
+dt:target, span.highlighted {
+    background-color: #f5f5f5
+}
+
diff --git a/docs/conf.py b/docs/conf.py
index 2e5ab0ee..2afaeb4e 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -56,6 +56,7 @@ extensions = [
     "sphinx.ext.coverage",
     "numpydoc",
     "sphinx_copybutton",
+    "sphinxcontrib.bibtex",
 ]
 
 # Generate the API documentation when building
diff --git a/docs/refs.bib b/docs/refs.bib
new file mode 100644
index 00000000..6d2cd068
--- /dev/null
+++ b/docs/refs.bib
@@ -0,0 +1,629 @@
+@Book{2007:ritto,
+  author = {Ritto, Thiago G.},
+  author = {Sampaio, Rubens.},
+  title = {Rotor Dynamics with MATLAB - Finite Element Analysis},
+  publisher = {PUC-Rio},
+  year = {2007}
+}
+
+@book{friswell2010dynamics,
+	title={Dynamics of rotating machines},
+	author={Friswell, Michael I},
+	year={2010},
+	publisher={Cambridge University Press}
+}
+
+@book{jaynes2003probability,
+  title={Probability theory: the logic of science},
+  author={Jaynes, Edwin T},
+  year={2003},
+  publisher={Cambridge university press}
+}
+
+@book{boyd2004convex,
+  title={Convex optimization},
+  author={Boyd, Stephen and Vandenberghe, Lieven},
+  year={2004},
+  publisher={Cambridge university press}
+}
+
+@article{zang2005review,
+  title={A review of robust optimal design and its application in dynamics},
+  author={Zang, C and Friswell, MI and Mottershead, JE},
+  journal={Computers \& structures},
+  volume={83},
+  number={4-5},
+  pages={315--326},
+  year={2005},
+  publisher={Elsevier}
+}
+
+@article{ritto2011robust,
+  title={Robust optimization of a flexible rotor-bearing system using the Campbell diagram},
+  author={Ritto, TG and Lopez, RH and Sampaio, R and Souza de Cursi, JE},
+  journal={Engineering Optimization},
+  volume={43},
+  number={1},
+  pages={77--96},
+  year={2011},
+  publisher={Taylor \& Francis}
+}
+
+@inproceedings{ishimoto2012early,
+title={Early detection of rotating stall phenomenon in centrifugal compressors by means of ASME PTC 10 type 2 test},
+author={Ishimoto, Leonardo and Silva, RT and Rangel Jr, JS and Miranda, MA and Audehove, FN and Marques, BS and Baldassarre, L and Puaut, C},
+booktitle={Proceedings of the Forty-First Turbomachinery Symposium, Houston, TX, Sept},
+pages={24--27},
+year={2012}
+}
+
+@inproceedings{baldassarre2007rotor,
+	title={Rotor Bearing Loads with Honeycomb Seals and Volute Forces in Reinjection Compressors},
+	author={Baldassarre, Leonardo and Fulton, John W},
+	booktitle={Proceedings of the Thirty-Sixth Turbomachinery Symposium},
+	pages={11--20},
+	year={2007}
+}
+
+@inproceedings{baldassarre2014,
+	title={Honeycomb seal effect on rotor response to unbalance},
+	author={Baldassarre,Leonardo and Bernocchi,Andrea and Failli,Leonardo and  Fontana,Michele and Mitaritonna,Nicola and Rizzo,Emanuele},
+	booktitle={Proceedings of the Forty-Third Turbomachinery Symposium, Houston, TX, Sept},
+	pages={},
+	year={2014}
+}
+
+@inproceedings{noronha2014stability,
+	title={Stability testing of CO2 compressors},
+	author={Noronha, Roberto Firmento and Cavalca, Katia Lucchesi and Miranda,
+         Marcelo Accorsi and Memmott, Edmund A. and Ramesh, Krish},
+	booktitle={Proceedings of the Forty-Third Turbomachinery Symposium, Houston, TX, Sept},
+	pages={},
+	year={2014}
+}
+
+@inproceedings{baldassarre2016effect,
+	title={Effect Of Relative Journal Bearing And Honeycomb Seal Direct Stiffness On Radial Synchronous Vibrations Of High-Pressure Centrifugal Compressors},
+	author={Baldassarre, Leonardo and Fontana, Michele and Bernocchi, Andrea and Moretti, Michele and others},
+	booktitle={Proceedings of the 45th Turbomachinery Symposium},
+	year={2016},
+	organization={Texas A\&M University. Turbomachinery Laboratories}
+}
+
+@inproceedings{vannini2011development,
+title={Development of a High Pressure Rotordynamic Test Rig for Centrifugal Compressors Internal Seals Characterization},
+author={Vannini, Giuseppe and Cioncolini, S and Calicchio, V and Tedone, Francesco},
+booktitle={Proceedings of the Fortieth Turbomachinery Symposium, Houston, TX, September},
+pages={12--15},
+year={2011}
+}
+
+@inproceedings{wagner2009investigations,
+	title={Investigations on the dynamic coefficients of impeller eye labyrinth seals},
+	author={Wagner, Norbert G and Steff, Klaus and Gausmann, Rainer and Schmidt, Marcus},
+	booktitle={Proceedings of the Thirty-Eighth Turbomachinery Symposium, Houston, TX, September},
+	pages={14--17},
+	year={2009}
+}
+
+@inproceedings{baumann1999rotordynamic,
+	title={Rotordynamic stability tests on high-pressure radial compressors},
+	author={Baumann, Urs},
+	booktitle={Proceedings of the 28th Turbomachinery Symposium, Turbomachinery Laboratory, Texas A\&M University, College Station, TX, September},
+	pages={12--15},
+	year={1999}
+}
+
+@inproceedings{moore2002rotordynamic,
+	title={Rotordynamic Stability Measurement During Full-Load, Full-Pressure Testing of a 6000 Psi Re-Injection Centrifugal Compressor},
+	author={Moore, J Jeffrey and Walker, Stephen T and Kuzdzal, Mark J},
+	booktitle={Proc. Of the Thirty-first Turbomachinery Symposium, Turbomachinery Laboratory, Department of Mechanical Engineering, Texas A\&M University, College Station, Texas},
+	year={2002}
+}
+
+@inproceedings{kocur2007surveying,
+	title={Surveying tilting pad journal bearing and gas labyrinth seal coefficients and their effect on rotor stability},
+	author={Kocur, John A and Nicholas, John C and Lee, Chester C},
+	booktitle={36th Turbomachinery Symposium, Turbomachinery Laboratory, Texas A\&M University, College Station, TX, September},
+	pages={10--13},
+	year={2007}
+}
+
+@inproceedings{kleynhans1996acoustic,
+	title={The acoustic influence of cell depth on the rotordynamic characteristics of smooth-rotor/honeycomb-stator annular gas seals},
+	author={Kleynhans, George F and Childs, Dara W},
+	booktitle={ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition},
+	pages={V005T14A017--V005T14A017},
+	year={1996},
+	organization={American Society of Mechanical Engineers}
+	
+}
+
+@phdthesis{kleynhans1996,
+	title={A two-control-volume bulk-flow rotordynamic analysis for smooth-rotor/honeycomb-stator gas annular seals},
+	author={Kleynhans, George Frederick},
+	year={1996},
+	school={Texas A\&M University}
+}
+
+@MastersThesis{wade2004,
+	title={Test Versus Predictions for Rotordynamic Coefficients and Leakage Rates of Hole-Pattern Gas Seals at Two Clearances in Choked and Unchoked Conditions},
+	author={Wade, Jonathan Leigh},
+	year={2004},
+	school={Texas A\&M University}
+}
+
+@MastersThesis{vannarsdall2011,
+	title={Measured Results For A New Hole-Pattern Annular Gas Seal Incorporating Larger Diameter Holes, Comparisons To Results For A Traditional Hole-Pattern Seal, And Predictions},
+	author={Vannarsdall, Michael Lloyd},
+	year={2011},
+	school={Texas A\&M University}
+}
+
+@article{beyer2007robust,
+  title={Robust optimization--a comprehensive survey},
+  author={Beyer, Hans-Georg and Sendhoff, Bernhard},
+  journal={Computer methods in applied mechanics and engineering},
+  volume={196},
+  number={33-34},
+  pages={3190--3218},
+  year={2007},
+  publisher={Elsevier}
+}
+
+@article{hirs1973bulk,
+	title={A bulk-flow theory for turbulence in lubricant films},
+	author={Hirs, GG},
+	journal={Journal of Lubrication Technology},
+	volume={95},
+	number={2},
+	pages={137--145},
+	year={1973},
+	publisher={American Society of Mechanical Engineers}
+}
+
+@article{nelson1984analysis,
+	title={Analysis for leakage and rotordynamic coefficients of surface-roughened tapered annular gas seals},
+	author={Nelson, CC},
+	journal={ASME J. Eng. Gas Turbines Power},
+	volume={106},
+	number={4},
+	pages={927--934},
+	year={1984}
+}
+
+@article{vonprogenau1982,
+    author={{von} Pragenau, George L},
+	title={Damping seal for turbomachinery},
+	journal = {Marshall Space Flight Center, Huntsville, AL, NASA TP-1987},
+	year = {1982},
+}
+
+@inproceedings{childs1997,
+	title={Annular gas seals and rotordynamics of compressors and turbines},
+	author={Childs, Dara W and Vance, John M},
+	booktitle={Proceedings of the 26th Turbomachinery Symposium},
+	pages={201--220},
+	year={1997}
+}
+
+@inproceedings{geary1976design,
+	title={Design and Operation of the WorldTs Highest Pressure Gas Injection Centrifugal Compressors},
+	author={Geary Jr, Carl H and Damratowski, Leonard P and Seyer, Chet H and others},
+	booktitle={Offshore Technology Conference},
+	year={1976},
+	organization={Offshore Technology Conference}
+}
+
+@inproceedings{noronha2015applying,
+  title={Applying CFD to Solve a Vibration Problem of a Compressor},
+  author={Noronha, Roberto Firmento de and Ujihara, Diogo Yoshikazu and Rezende-Tapajoz, Leticia de and Grosso, Glenn and Moreira, Ridrigo Peralta Muniz and others},
+  booktitle={Proceedings of the 44th Turbomachinery Symposium},
+  year={2015},
+  organization={Turbomachinery Laboratories, Texas A\&M Engineering Experiment Station}
+}
+
+@article{api684,
+	title={API 684, 2005},
+	author={API 684, API 684},
+	journal={Tutorial on Rotordynamics: Lateral Critical, Unbalance Response, Stability, Train Torsional and Rotor Balancing,” Second Edition, American Petroleum Institute, Washington, DC},
+	year={2005}
+}
+
+@article{api617,
+	title={API 617, 2014},
+	author={API 617, API 617},
+	journal={Axial and Centrifugal Compressors and Expander-Compressors” Eighth Edition, American Petroleum Institute, Washington, DC},
+	year={2014}
+}
+
+@book{ludtke2013process,
+	title={Process centrifugal compressors: basics, function, operation, design, application},
+	author={L{\"u}dtke, Klaus H},
+	year={2013},
+	publisher={Springer Science \& Business Media}
+}
+
+@article{he2004thermoelastohydrodynamic,
+	title={Thermoelastohydrodynamic analysis of fluid film journal bearings.},
+	author={He, Minhui},
+	year={2004}
+}
+
+@article{migliorini2012computational,
+	title={A computational fluid dynamics/bulk-flow hybrid method for determining rotordynamic coefficients of annular gas seals},
+	author={Migliorini, Patrick J and Untaroiu, Alexandrina and Wood, Houston G and Allaire, Paul E},
+	journal={Journal of Tribology},
+	volume={134},
+	number={2},
+	pages={022202},
+	year={2012},
+	publisher={American Society of Mechanical Engineers}
+}
+
+@article{walt2011numpy,
+  title={The NumPy array: a structure for efficient numerical computation},
+  author={Walt, St{\'e}fan van der and Colbert, S Chris and Varoquaux, Gael},
+  journal={Computing in Science \& Engineering},
+  volume={13},
+  number={2},
+  pages={22--30},
+  year={2011},
+  publisher={IEEE}
+}
+
+@article{hunter2007matplotlib,
+  title={Matplotlib: A 2D graphics environment},
+  author={Hunter, John D},
+  journal={Computing in science \& engineering},
+  volume={9},
+  number={3},
+  pages={90--95},
+  year={2007},
+  publisher={IEEE}
+}
+
+@article{jones2014scipy,
+  title={SciPy: open source scientific tools for Python},
+  author={Jones, Eric and Oliphant, Travis and Peterson, Pearu},
+  year={2014}
+}
+
+@article{turbomachinery2002xltrc2,
+  title={XLTRC2 Rotordynamics Software Suite (2002)},
+  author={Turbomachinery Research Consortium},
+  journal={Turbomachinery Laboratory, Texas A\&M University, College Station, TX},
+  year={2002}
+}
+
+@article{childs2014impact,
+  title={The Impact of Hole Depth on the Rotordynamic and Leakage Characteristics of Hole-Pattern-Stator Gas Annular Seals},
+  author={Childs, Dara W and Arthur, Stephen and Mehta, Naitik J},
+  journal={Journal of Engineering for Gas Turbines and Power},
+  volume={136},
+  number={4},
+  pages={042501},
+  year={2014},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{childs1978,
+  title={The Space Shuttle Main Engine High-pressure Fuel Turbopump
+         Rotordynamic Instability Problem},
+  author={Childs, Dara W},
+  journal={Journal of Engineering for Power},
+  volume={100},
+  number={4},
+  pages={48-57},
+  year={1978},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{childs2004rotordynamic,
+  title={Rotordynamic-Coefficient and Leakage Characteristics for Hole-Pattern-Stator Annular Gas Seals—Measurements Versus Predictions},
+  author={Childs, Dara W and Wade, Jonathan},
+  journal={Journal of tribology},
+  volume={126},
+  number={2},
+  pages={326--333},
+  year={2004},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@misc{vonpragenau1985damping,
+  title={Damping seal for turbomachinery},
+  author={{von} Pragenau, George L},
+  year={1985},
+  month=oct # "~8",
+  publisher={Google Patents},
+  note={US Patent 4,545,586}
+}
+
+@article{black1969effects,
+  title={Effects of hydraulic forces in annular pressure seals on the vibrations of centrifugal pump rotors},
+  author={Black, HF},
+  journal={Journal of Mechanical Engineering Science},
+  volume={11},
+  number={2},
+  pages={206--213},
+  year={1969},
+  publisher={SAGE Publications Sage UK: London, England}
+}
+
+@inproceedings{black1981inlet,
+  title={Inlet Flow Swirl in Short Turbulent Annular Seal Dynamics},
+  author={Black, HF and Allaire, PE and Barrett, LE},
+  booktitle={Proceedings of the Ninth International Conference in Fluid Sealing},
+  pages={1--3},
+  year={1981}
+}
+
+@book{childs1993turbomachinery,
+  title={Turbomachinery rotordynamics: phenomena, modeling, and analysis},
+  author={Childs, Dara W},
+  year={1993},
+  publisher={John Wiley \& Sons}
+}
+
+@article{childs1983dynamic,
+  title={Dynamic analysis of turbulent annular seals based on Hirs’ lubrication equation},
+  author={Childs, Dara W},
+  journal={Journal of lubrication technology},
+  volume={105},
+  number={3},
+  pages={429--436},
+  year={1983},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{childs1983finite,
+  title={Finite-length solutions for rotordynamic coefficients of turbulent annular seals},
+  author={Childs, Dara W},
+  journal={Journal of lubrication technology},
+  volume={105},
+  number={3},
+  pages={437--444},
+  year={1983},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{nelson1985rotordynamic,
+  title={Rotordynamic coefficients for compressible flow in tapered annular seals},
+  author={Nelson, CC},
+  journal={Journal of Tribology},
+  volume={107},
+  number={3},
+  pages={318--325},
+  year={1985},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{elrod1989entrance,
+  title={An Entrance Region Friction Factor Model Applied to Annular Seal Analysis: Theory Versus Experiment for Smooth and Honeycomb Seals},
+  author={Elrod, D and Nelson, C and Childs, D},
+  journal={Journal of tribology},
+  volume={111},
+  number={2},
+  pages={337--343},
+  year={1989},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{ha1992friction,
+  title={Friction-factor data for flat-plate tests of smooth and honeycomb surfaces},
+  author={Ha, Tae Woong and Childs, Dara W},
+  journal={Journal of tribology},
+  volume={114},
+  number={4},
+  pages={722--729},
+  year={1992},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{ha1994annular,
+  title={Annular Honeycomb-Stator Turbulent Gas Seal Analysis Using a New Friction-Factor Model Based on Flat Plate Tests},
+  author={Ha, Tae Woong and Childs, DW},
+  journal={Journal of tribology},
+  volume={116},
+  number={2},
+  pages={352--359},
+  year={1994},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{ha1992characteristics,
+  title={Friction-factor characteristics for narrow channels with honeycomb surfaces},
+  author={Ha, TW and Morrison, GL and Childs, DW},
+  journal={Journal of tribology},
+  volume={114},
+  number={4},
+  pages={714--721},
+  year={1992},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{migliorini2015numerical,
+  title={A Numerical Study on the Influence of Hole Depth on the Static and Dynamic Performance of Hole-Pattern Seals},
+  author={Migliorini, Patrick J and Untaroiu, Alexandrina and Wood, Houston G},
+  journal={Journal of Tribology},
+  volume={137},
+  number={1},
+  pages={011702},
+  year={2015},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{childs1989annular,
+  title={Annular honeycomb seals: Test results for leakage and rotordynamic coefficients; comparisons to labyrinth and smooth configurations},
+  author={Childs, Dara and Elrod, David and Hale, Keith},
+  journal={Journal of Tribology},
+  volume={111},
+  number={2},
+  pages={293--300},
+  year={1989},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{holt2002theory,
+  title={Theory versus experiment for the rotordynamic impedances of two hole-pattern-stator gas annular seals},
+  author={Holt, Christopher G and Childs, Dara W},
+  journal={Journal of tribology},
+  volume={124},
+  number={1},
+  pages={137--143},
+  year={2002},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{vannarsdall2014static,
+  title={Static and Rotordynamic Characteristics for a New Hole-Pattern Annular Gas Seal Design Incorporating Larger Diameter Holes},
+  author={Vannarsdall, Michael and Childs, Dara W},
+  journal={Journal of Engineering for Gas Turbines and Power},
+  volume={136},
+  number={2},
+  pages={022507},
+  year={2014},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@mastersthesis{rondon2014thrust,
+  title={Thrust gas bearing analytical tool development},
+  author={Rondon, David},
+  year={2014},
+  school={NTNU}
+}
+
+@article{cowper1966shear,
+  title={The shear coefficient in Timoshenko’s beam theory},
+  author={Cowper, GR},
+  journal={Journal of applied mechanics},
+  volume={33},
+  number={2},
+  pages={335--340},
+  year={1966},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{scharrer1994discussion,
+  title={Discussion:“Annular Honeycomb-Stator Turbulent Gas Seal Analysis Using a New Friction-Factor Model Based on Flat Plate Tests”(Ha, TW, and Childs, DW, 1994, ASME J. Tribol., 116, pp. 352--359)},
+  author={Scharrer, J},
+  journal={Journal of Tribology},
+  volume={116},
+  number={2},
+  pages={359--359},
+  year={1994},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{scharrer1988theory,
+  title={Theory versus experiment for the rotordynamic coefficients of labyrinth gas seals: part I—a two control volume model},
+  author={Scharrer, Joseph K},
+  journal={Journal of Vibration, Acoustics, Stress, and Reliability in Design},
+  volume={110},
+  number={3},
+  pages={270--280},
+  year={1988},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{iso1940,
+  title={Mechanical Vibration-Balance Quality Requirements of Rigid Rotors},
+  author={ISO 1940, Standard},
+  journal={Part I: Determination of Permissible Residual Unbalance,},
+  year={1998}
+}
+
+@book{inman1994engineering,
+  title={Engineering vibration},
+  author={Inman, Daniel J},
+  year={2013},
+  publisher={Pearson; 4 edition}
+}
+
+@inproceedings{zeidan1993use,
+  title={The Use Of Honeycomb Seals In Stabilizing Two Centrifugal Compressors.},
+  author={Zeidan, Fouad Y and Perez, Robert X and Stephenson, E Morris and others},
+  booktitle={Proceedings of the 22nd Turbomachinery Symposium},
+  year={1993},
+  organization={Texas A\&M University. Turbomachinery Laboratories}
+}
+
+@inproceedings{sorokes1994recent,
+  title={Recent Experiences In Full Load Full Pressure Shop Testing Of A High Pressure Gas Injection Centrifugal Compressor.},
+  author={Sorokes, James M and Kuzdzal, Mark J and Sandberg, Mark R and Colby, Gary M and others},
+  booktitle={Proceedings of the 23rd Turbomachinery Symposium},
+  year={1994},
+  organization={Texas A\&M University. Turbomachinery Laboratories}
+}
+
+@article{gelin1997experience,
+  title={Experience in full-load testing of natural gas centrifugal compressors for rotordynamics improvements},
+  author={Gelin, Alain and Pugnet, J-M and Bolusset, Daniel and Friez, Patrick},
+  journal={Journal of engineering for gas turbines and power},
+  volume={119},
+  number={4},
+  pages={934--941},
+  year={1997},
+  publisher={American Society of Mechanical Engineers}
+}
+
+@article{Ritto11,
+	title={Robust optimization of a flexible rotor-bearing system using the Campbell diagram},
+	author={Ritto, TG and Lopez, RH and Sampaio, R and Souza De Cursi, JE},
+	journal={Engineering Optimization},
+	volume={43},
+	number={1},
+	pages={77--96},
+	year={2011}
+}
+
+@article{Tyminski17,
+	title={Bayesian inference applied to journal bearing parameter identification},
+	author={Tyminski, NC and Tuckmantel, FWS and Cavalca, KL and de Castro, HF},
+	journal={Journal of the Brazilian Society of Mechanical Sciences and Engineering},
+	volume={29},
+	number={8},
+	pages={2983--3004},
+	year={2017}
+}
+
+@article{Murthy10,
+	title={Nonparametric stochastic modeling of uncertainty in rotordynamics-part 1: Formulation},
+	author={Murthy, R and Mignolet, MP and El-Shafei, A},
+	journal={Journal of Engineering for Gas Turbines and Power},
+	volume={132},
+	number={9},
+	pages={092501},
+	year={2010}
+}
+
+@article{Cavalini17,
+	title={Dynamic analysis of a flexible rotor supported by hydrodynamic bearings with uncertain parameters},
+	author={Cavalini, AA and Silva, ADG and Lara-Molina, FA and Steffen, V},
+	journal={Meccanica},
+	volume={1},
+	number={9},
+	pages={1-12},
+	year={2017}
+}
+
+@article{Lara2015,
+	title={Uncertainty Analysis of a Flexible Rotors considering fuzzy parameters and fuzzy-random parameters},
+	author={Lara-Molina, FA and Koroishi, EH and Steffen Jr, V},
+	journal={Latin American Journal of Solids and Structures},
+	volume={12},
+	number={9},
+	pages={1807-1823},
+	year={2015}
+}
+
+@article{Koroishi2012,
+	title={Stochastic Modeling of Flexible Rotors},
+	author={Koroishi, EH and Cavalini, AA and Lima, AMG and Steffen Jr, V},
+	journal={Brazilian Society of Mechanical Sciences and Engineering},
+	volume={34},
+	number={9},
+	pages={574-583},
+	year={2012}
+}
+
diff --git a/ross/bearing_seal_element.py b/ross/bearing_seal_element.py
index 927ba67d..da956d65 100644
--- a/ross/bearing_seal_element.py
+++ b/ross/bearing_seal_element.py
@@ -56,7 +56,8 @@ class _Coefficient:
                         )
                 except:
                     raise ValueError(
-                        "Arguments (coefficients and w)" " must have the same dimension"
+                        "Arguments (coefficients and frequency)"
+                        " must have the same dimension"
                     )
         else:
             self.interpolated = lambda x: np.array(self.coefficient[0])
@@ -104,12 +105,14 @@ class _Damping_Coefficient(_Coefficient):
 
 class BearingElement(Element):
     """A bearing element.
+
     This class will create a bearing element.
     Parameters can be a constant value or speed dependent.
     For speed dependent parameters, each argument should be passed
     as an array and the correspondent speed values should also be
     passed as an array.
     Values for each parameter will be interpolated for the speed.
+
     Parameters
     ----------
     n: int
@@ -136,8 +139,8 @@ class BearingElement(Element):
     cyx: float, array, optional
         Cross coupled damping in the y direction.
         (defaults to 0)
-    w: array, optional
-        Array with the speeds (rad/s).
+    frequency: array, optional
+        Array with the frequencies (rad/s).
     tag: str, optional
         A tag to name the element
         Default is None.
@@ -148,6 +151,7 @@ class BearingElement(Element):
     scale_factor: float, optional
         The scale factor is used to scale the bearing drawing.
         Default is 1.
+
     Examples
     --------
     >>> # A bearing element located in the first rotor node, with these
@@ -158,11 +162,11 @@ class BearingElement(Element):
     >>> kyy = 0.8e6
     >>> cxx = 2e2
     >>> cyy = 1.5e2
-    >>> w = np.linspace(0, 200, 11)
-    >>> bearing0 = rs.BearingElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, w=w)
-    >>> bearing0.K(w) # doctest: +ELLIPSIS
+    >>> frequency = np.linspace(0, 200, 11)
+    >>> bearing0 = rs.BearingElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, frequency=frequency)
+    >>> bearing0.K(frequency) # doctest: +ELLIPSIS
     array([[[1000000., 1000000., ...
-    >>> bearing0.C(w) # doctest: +ELLIPSIS
+    >>> bearing0.C(frequency) # doctest: +ELLIPSIS
     array([[[200., 200., ...
     """
 
@@ -177,7 +181,7 @@ class BearingElement(Element):
         cyy=None,
         cxy=0,
         cyx=0,
-        w=None,
+        frequency=None,
         tag=None,
         n_link=None,
         scale_factor=1,
@@ -197,24 +201,28 @@ class BearingElement(Element):
         for arg in args:
             if arg[0] == "k":
                 coefficients[arg] = _Stiffness_Coefficient(
-                    coefficient=args_dict[arg], w=args_dict["w"]
+                    coefficient=args_dict[arg], w=args_dict["frequency"]
                 )
             else:
-                coefficients[arg] = _Damping_Coefficient(args_dict[arg], args_dict["w"])
+                coefficients[arg] = _Damping_Coefficient(
+                    args_dict[arg], args_dict["frequency"]
+                )
 
         coefficients_len = [len(v.coefficient) for v in coefficients.values()]
 
-        if w is not None and type(w) != float:
-            coefficients_len.append(len(args_dict["w"]))
+        if frequency is not None and type(frequency) != float:
+            coefficients_len.append(len(args_dict["frequency"]))
             if len(set(coefficients_len)) > 1:
                 raise ValueError(
-                    "Arguments (coefficients and w)" " must have the same dimension"
+                    "Arguments (coefficients and frequency)"
+                    " must have the same dimension"
                 )
         else:
             for c in coefficients_len:
                 if c != 1:
                     raise ValueError(
-                        "Arguments (coefficients and w)" " must have the same dimension"
+                        "Arguments (coefficients and frequency)"
+                        " must have the same dimension"
                     )
 
         for k, v in coefficients.items():
@@ -225,7 +233,7 @@ class BearingElement(Element):
         self.n_l = n
         self.n_r = n
 
-        self.w = np.array(w, dtype=np.float64)
+        self.frequency = np.array(frequency, dtype=np.float64)
         self.tag = tag
         self.color = "#355d7a"
         self.scale_factor = scale_factor
@@ -252,7 +260,7 @@ class BearingElement(Element):
             f" kyx={self.kyx}, kyy={self.kyy},\n"
             f" cxx={self.cxx}, cxy={self.cxy},\n"
             f" cyx={self.cyx}, cyy={self.cyy},\n"
-            f" w={self.w}, tag={self.tag!r})"
+            f" frequency={self.frequency}, tag={self.tag!r})"
         )
 
     def __eq__(self, other):
@@ -282,7 +290,7 @@ class BearingElement(Element):
             "cyy",
             "cxy",
             "cyx",
-            "w",
+            "frequency",
             "n",
         ]
         if isinstance(other, self.__class__):
@@ -299,8 +307,9 @@ class BearingElement(Element):
         return hash(self.tag)
 
     def save(self, file_name):
-        """Saves a bearing element in a toml format. It works as an auxiliary function of
-        the save function in the Rotor class.
+        """Saves a bearing element in a toml format. It works as an auxiliary
+        function of the save function in the Rotor class.
+
         Parameters
         ----------
         file_name: string
@@ -316,12 +325,12 @@ class BearingElement(Element):
         >>> bearing.save('BearingElement.toml')
         """
         data = self.load_data(file_name)
-        if type(self.w) == np.ndarray:
+        if type(self.frequency) == np.ndarray:
             try:
-                self.w[0]
-                w = list(self.w)
+                self.frequency[0]
+                frequency = list(self.frequency)
             except IndexError:
-                w = None
+                frequency = None
         data["BearingElement"][str(self.n)] = {
             "n": self.n,
             "kxx": self.kxx.coefficient,
@@ -332,7 +341,7 @@ class BearingElement(Element):
             "cyy": self.cyy.coefficient,
             "cxy": self.cxy.coefficient,
             "cyx": self.cyx.coefficient,
-            "w": w,
+            "frequency": frequency,
             "tag": self.tag,
         }
         self.dump_data(data, file_name)
@@ -340,6 +349,7 @@ class BearingElement(Element):
     @staticmethod
     def load(file_name="BearingElement"):
         """Loads a list of bearing elements saved in a toml format.
+
         Parameters
         ----------
         file_name: string
@@ -399,20 +409,6 @@ class BearingElement(Element):
         return bearing_elements
 
     def dof_mapping(self):
-        """Returns a dictionary with a mapping between degree of freedom and its index.
-        Parameters
-        ----------
-
-        Returns
-        -------
-        A dictionary containing the degrees of freedom and their indexes.
-
-        Examples
-        --------
-        >>> bearing = bearing_example()
-        >>> bearing.dof_mapping()
-        {'x_0': 0, 'y_0': 1}
-        """
         return dict(x_0=0, y_0=1)
 
     def dof_global_index(self):
@@ -429,13 +425,12 @@ class BearingElement(Element):
         return global_index
 
     def M(self):
-        """Returns the mass matrix.
-        Parameters
-        ----------
+        """Mass matrix.
 
         Returns
         -------
-        A matrix of floats.
+        M: np.ndarray
+            Mass matrix.
 
         Examples
         --------
@@ -448,16 +443,18 @@ class BearingElement(Element):
 
         return M
 
-    def K(self, w):
-        """Returns the stiffness matrix for a given speed.
+    def K(self, frequency):
+        """Returns the stiffness matrix for a given excitation frequency.
+
         Parameters
         ----------
-        w: float
-            The speeds (rad/s) to consider.
+        frequency: float
+            The excitation frequency (rad/s).
 
         Returns
         -------
-        A 2x2 matrix of floats containing the kxx, kxy, kyx, and kyy values.
+        K: np.ndarray
+            A 2x2 matrix of floats containing the kxx, kxy, kyx, and kyy values.
 
         Examples
         --------
@@ -466,10 +463,10 @@ class BearingElement(Element):
         array([[1000000.,       0.],
                [      0.,  800000.]])
         """
-        kxx = self.kxx.interpolated(w)
-        kyy = self.kyy.interpolated(w)
-        kxy = self.kxy.interpolated(w)
-        kyx = self.kyx.interpolated(w)
+        kxx = self.kxx.interpolated(frequency)
+        kyy = self.kyy.interpolated(frequency)
+        kxy = self.kxy.interpolated(frequency)
+        kyx = self.kyx.interpolated(frequency)
 
         K = np.array([[kxx, kxy], [kyx, kyy]])
 
@@ -481,16 +478,18 @@ class BearingElement(Element):
 
         return K
 
-    def C(self, w):
-        """Returns the damping matrix for a given speed.
+    def C(self, frequency):
+        """Returns the damping matrix for a given excitation frequency.
+
         Parameters
         ----------
-        w: float
-            The speeds (rad/s) to consider.
+        frequency: float
+            The excitation frequency (rad/s).
 
         Returns
         -------
-        A 2x2 matrix of floats containing the cxx, cxy, cyx, and cyy values.
+        C: np.ndarray
+            A 2x2 matrix of floats containing the cxx, cxy, cyx, and cyy values.
 
         Examples
         --------
@@ -499,10 +498,10 @@ class BearingElement(Element):
         array([[200.,   0.],
                [  0., 150.]])
         """
-        cxx = self.cxx.interpolated(w)
-        cyy = self.cyy.interpolated(w)
-        cxy = self.cxy.interpolated(w)
-        cyx = self.cyx.interpolated(w)
+        cxx = self.cxx.interpolated(frequency)
+        cyy = self.cyy.interpolated(frequency)
+        cxy = self.cxy.interpolated(frequency)
+        cyx = self.cyx.interpolated(frequency)
 
         C = np.array([[cxx, cxy], [cyx, cyy]])
 
@@ -515,13 +514,12 @@ class BearingElement(Element):
         return C
 
     def G(self):
-        """Returns the giroscopic matrix.
-        Parameters
-        ----------
+        """Gyroscopic matrix.
 
         Returns
         -------
-        A matrix of floats.
+        G: np.ndarray
+            A 2x2 matrix of floats.
 
         Examples
         --------
@@ -740,18 +738,23 @@ class BearingElement(Element):
 
     @classmethod
     def table_to_toml(cls, n, file):
-        """Convert a table with parameters of a bearing element to a dictionary ready to save
+        """Convert bearing parameters to toml.
+
+        Convert a table with parameters of a bearing element to a dictionary ready to save
         to a toml file that can be later loaded by ross.
+
         Parameters
         ----------
         n : int
             The node in which the bearing will be located in the rotor.
         file: str
             Path to the file containing the bearing parameters.
+
         Returns
         -------
-        dict
+        data: dict
             A dict that is ready to save to toml and readable by ross.
+
         Examples
         --------
         >>> import os
@@ -770,16 +773,18 @@ class BearingElement(Element):
             "cyy": b_elem.cyy.coefficient,
             "cxy": b_elem.cxy.coefficient,
             "cyx": b_elem.cyx.coefficient,
-            "w": b_elem.w,
+            "frequency": b_elem.frequency,
         }
         return data
 
     @classmethod
     def from_table(cls, n, file, sheet_name=0, **kwargs):
         """Instantiate a bearing using inputs from an Excel table.
+
         A header with the names of the columns is required. These names should match the names expected by the routine
         (usually the names of the parameters, but also similar ones). The program will read every row bellow the header
         until they end or it reaches a NaN.
+
         Parameters
         ----------
         n : int
@@ -789,9 +794,12 @@ class BearingElement(Element):
         sheet_name: int or str, optional
             Position of the sheet in the file (starting from 0) or its name. If none is passed, it is
             assumed to be the first sheet in the file.
+
         Returns
         -------
-        A bearing object.
+        bearing: rs.BearingElement
+            A bearing object.
+
         Examples
         --------
         >>> import os
@@ -811,7 +819,7 @@ class BearingElement(Element):
             cyy=parameters["cyy"],
             cxy=parameters["cxy"],
             cyx=parameters["cyx"],
-            w=parameters["w"],
+            frequency=parameters["frequency"],
             **kwargs,
         )
 
@@ -834,10 +842,12 @@ class BearingElement(Element):
         load=None,
     ):
         """Instantiate a bearing using inputs from its fluid flow.
+
         Parameters
         ----------
         n : int
             The node in which the bearing will be located in the rotor.
+
         Grid related
         ^^^^^^^^^^^^
         Describes the discretization of the problem
@@ -880,9 +890,12 @@ class BearingElement(Element):
             Viscosity (Pa.s).
         rho: float
             Fluid density(Kg/m^3).
+
         Returns
         -------
-        A bearing object.
+        bearing: rs.BearingElement
+            A bearing object.
+
         Examples
         --------
         >>> nz = 30
@@ -937,18 +950,20 @@ class BearingElement(Element):
             cyy=c[3],
             cxy=c[1],
             cyx=c[2],
-            w=fluid_flow.omega,
+            frequency=fluid_flow.omega,
         )
 
 
 class SealElement(BearingElement):
     """A seal element.
+
     This class will create a seal element.
     Parameters can be a constant value or speed dependent.
     For speed dependent parameters, each argument should be passed
     as an array and the correspondent speed values should also be
     passed as an array.
     Values for each parameter will be interpolated for the speed.
+
     Parameters
     ----------
     n: int
@@ -975,13 +990,14 @@ class SealElement(BearingElement):
     cyx: float, array, optional
         Cross coupled damping in the y direction.
         (defaults to 0)
-    w: array, optional
+    frequency: array, optional
         Array with the speeds (rad/s).
     seal_leakage: float, optional
         Amount of leakage
     tag : str, optional
         A tag to name the element
         Default is None
+
     Examples
     --------
     >>> # A seal element located in the first rotor node, with these
@@ -992,11 +1008,11 @@ class SealElement(BearingElement):
     >>> kyy = 0.8e6
     >>> cxx = 2e2
     >>> cyy = 1.5e2
-    >>> w = np.linspace(0, 200, 11)
-    >>> seal = rs.SealElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, w=w)
-    >>> seal.K(w) # doctest: +ELLIPSIS
+    >>> frequency = np.linspace(0, 200, 11)
+    >>> seal = rs.SealElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, frequency=frequency)
+    >>> seal.K(frequency) # doctest: +ELLIPSIS
     array([[[1000000., 1000000., ...
-    >>> seal.C(w) # doctest: +ELLIPSIS
+    >>> seal.C(frequency) # doctest: +ELLIPSIS
     array([[[200., 200., ...
     """
 
@@ -1011,13 +1027,13 @@ class SealElement(BearingElement):
         cyy=None,
         cxy=0,
         cyx=0,
-        w=None,
+        frequency=None,
         seal_leakage=None,
         tag=None,
     ):
         super().__init__(
             n=n,
-            w=w,
+            frequency=frequency,
             kxx=kxx,
             kxy=kxy,
             kyx=kyx,
@@ -1181,7 +1197,7 @@ class BallBearingElement(BearingElement):
 
         super().__init__(
             n=n,
-            w=None,
+            frequency=None,
             kxx=kxx,
             kxy=0.0,
             kyx=0.0,
@@ -1471,7 +1487,7 @@ class RollerBearingElement(BearingElement):
 
         super().__init__(
             n=n,
-            w=None,
+            frequency=None,
             kxx=kxx,
             kxy=0.0,
             kyx=0.0,
@@ -1704,7 +1720,7 @@ def bearing_example():
     Examples
     --------
     >>> bearing = bearing_example()
-    >>> bearing.w[0]
+    >>> bearing.frequency[0]
     0.0
     """
     kxx = 1e6
@@ -1712,7 +1728,7 @@ def bearing_example():
     cxx = 2e2
     cyy = 1.5e2
     w = np.linspace(0, 200, 11)
-    bearing = BearingElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, w=w)
+    bearing = BearingElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, frequency=w)
     return bearing
 
 
@@ -1731,7 +1747,7 @@ def seal_example():
     Examples
     --------
     >>> seal = bearing_example()
-    >>> seal.w[0]
+    >>> seal.frequency[0]
     0.0
     """
     kxx = 1e6
@@ -1739,5 +1755,5 @@ def seal_example():
     cxx = 2e2
     cyy = 1.5e2
     w = np.linspace(0, 200, 11)
-    seal = SealElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, w=w)
+    seal = SealElement(n=0, kxx=kxx, kyy=kyy, cxx=cxx, cyy=cyy, frequency=w)
     return seal
diff --git a/ross/disk_element.py b/ross/disk_element.py
index 006db737..bfa6505b 100644
--- a/ross/disk_element.py
+++ b/ross/disk_element.py
@@ -13,7 +13,9 @@ bokeh_colors = bp.RdGy[11]
 
 class DiskElement(Element):
     """A disk element.
+
      This class will create a disk element from input data of inertia and mass.
+
      Parameters
      ----------
      n: int
@@ -27,15 +29,12 @@ class DiskElement(Element):
      tag : str, optional
          A tag to name the element
          Default is None
-     References
-     ----------
-     .. [1] 'Dynamics of Rotating Machinery' by MI Friswell, JET Penny, SD Garvey
-        & AW Lees, published by Cambridge University Press, 2010 pp. 156-157.
+
      Examples
      --------
-     >>> disk = DiskElement(0, 32.58972765, 0.17808928, 0.32956362)
+     >>> disk = DiskElement(n=0, m=32, Id=0.2, Ip=0.3)
      >>> disk.Ip
-     0.32956362
+     0.3
      """
 
     def __init__(self, n, m, Id, Ip, tag=None):
@@ -111,8 +110,11 @@ class DiskElement(Element):
         return hash(self.tag)
 
     def save(self, file_name):
-        """Saves a disk element in a toml format. It works as an auxiliary function of
-        the save function in the Rotor class.
+        """Saves a disk element in a toml format.
+
+        It works as an auxiliary function of the save function in the Rotor
+        class.
+
         Parameters
         ----------
         file_name: string
@@ -140,14 +142,16 @@ class DiskElement(Element):
     @staticmethod
     def load(file_name="DiskElement"):
         """Loads a list of disk elements saved in a toml format.
+
         Parameters
         ----------
-        file_name: string
+        file_name: str
             The name of the file of the disk element to be loaded.
 
         Returns
         -------
-        A list of disk elements.
+        disk_elements: list
+            A list of disk elements.
 
         Examples
         --------
@@ -167,13 +171,15 @@ class DiskElement(Element):
         return disk_elements
 
     def dof_mapping(self):
-        """Returns a dictionary with a mapping between degree of freedom and its index.
-        Parameters
-        ----------
+        """Degrees of freedom mapping.
+
+        Returns a dictionary with a mapping between degree of freedom and its
+        index.
 
         Returns
         -------
-        A dictionary containing the degrees of freedom and their indexes.
+        dof_mapping: dict
+            A dictionary containing the degrees of freedom and their indexes.
 
         Examples
         --------
@@ -184,15 +190,15 @@ class DiskElement(Element):
         return dict(x_0=0, y_0=1, alpha_0=2, beta_0=3)
 
     def M(self):
-        """
+        """Mass matrix.
+
         This method will return the mass matrix for an instance of a disk
         element.
-        Parameters
-        ----------
 
         Returns
         -------
         Mass matrix for the disk element.
+
         Examples
         --------
         >>> disk = DiskElement(0, 32.58972765, 0.17808928, 0.32956362)
@@ -213,13 +219,15 @@ class DiskElement(Element):
         return M
 
     def K(self):
-        """Returns the stiffness matrix.
-        Parameters
-        ----------
+        """Stiffness matrix.
+
+        This method will return the stiffness matrix for an instance of a disk
+        element.
 
         Returns
         -------
-        A matrix of floats containing the values of the stiffness matrix.
+        K: np.ndarray
+            A matrix of floats containing the values of the stiffness matrix.
 
         Examples
         --------
@@ -236,12 +244,11 @@ class DiskElement(Element):
 
     def C(self):
         """Returns the damping matrix.
-        Parameters
-        ----------
 
         Returns
         -------
-        A matrix of floats containing the values of the damping matrix.
+        C: np.ndarray
+            A matrix of floats containing the values of the damping matrix.
 
         Examples
         --------
@@ -257,15 +264,16 @@ class DiskElement(Element):
         return C
 
     def G(self):
-        """
+        """Gyroscopic matrix.
+
         This method will return the gyroscopic matrix for an instance of a disk
         element.
-        Parameters
-        ----------
 
         Returns
         -------
-        Gyroscopic matrix for the disk element.
+        G: np.ndarray
+            Gyroscopic matrix for the disk element.
+
         Examples
         --------
         >>> disk = DiskElement(0, 32.58972765, 0.17808928, 0.32956362)
@@ -287,17 +295,18 @@ class DiskElement(Element):
 
     def patch(self, position, ax):
         """Disk element patch.
+
         Patch that will be used to draw the disk element.
+
         Parameters
         ----------
         ax : matplotlib axes, optional
             Axes in which the plot will be drawn.
         position : float
             Position in which the patch will be drawn.
+
         Returns
         -------
-        ax : matplotlib axes
-            Returns the axes object with the plot.
         """
         zpos, ypos = position
         step = ypos / 5
@@ -430,12 +439,14 @@ class DiskElement(Element):
     @classmethod
     def from_geometry(cls, n, material, width, i_d, o_d, tag=None):
         """A disk element.
-        This class will create a disk element from input data of geometry.
+
+        This class method will create a disk element from geometry data.
+
         Parameters
         ----------
         n: int
             Node in which the disk will be inserted.
-        material : lavirot.Material
+        material: ross.Material
              Shaft material.
         width: float
             The disk width.
@@ -443,6 +454,7 @@ class DiskElement(Element):
             Inner diameter.
         o_d: float
             Outer diameter.
+
         Attributes
         ----------
         m : float
@@ -454,10 +466,7 @@ class DiskElement(Element):
         tag : str, optional
             A tag to name the element
             Default is None
-        References
-        ----------
-        .. [1] 'Dynamics of Rotating Machinery' by MI Friswell, JET Penny, SD Garvey
-           & AW Lees, published by Cambridge University Press, 2010 pp. 156-157.
+
         Examples
         --------
         >>> from ross.materials import steel
@@ -481,20 +490,24 @@ class DiskElement(Element):
     @classmethod
     def from_table(cls, file, sheet_name=0):
         """Instantiate one or more disks using inputs from an Excel table.
-        A header with the names of the columns is required. These names should match the names expected by the routine
-        (usually the names of the parameters, but also similar ones). The program will read every row bellow the header
-        until they end or it reaches a NaN.
+
+        A header with the names of the columns is required. These names should
+        match the names expected by the routine (usually the names of the
+        parameters, but also similar ones). The program will read every row
+        bellow the header until they end or it reaches a NaN.
+
         Parameters
         ----------
         file: str
             Path to the file containing the disk parameters.
         sheet_name: int or str, optional
-            Position of the sheet in the file (starting from 0) or its name. If none is passed, it is
-            assumed to be the first sheet in the file.
+            Position of the sheet in the file (starting from 0) or its name.
+            If none is passed, it is assumed to be the first sheet in the file.
         Returns
         -------
         disk : list
             A list of disk objects.
+
         Examples
         --------
         >>> import os
diff --git a/ross/element.py b/ross/element.py
index bbbd91b8..94760339 100644
--- a/ross/element.py
+++ b/ross/element.py
@@ -149,6 +149,7 @@ class Element(ABC):
         """A summary for the element.
 
         A pandas series with the element properties as variables.
+
         Parameters
         ----------
 
@@ -180,6 +181,7 @@ class Element(ABC):
     @staticmethod
     def load_data(file_name):
         """Loads elements data saved in a toml format.
+
         Parameters
         ----------
         file_name: string
@@ -187,8 +189,9 @@ class Element(ABC):
 
         Returns
         -------
-        dict
+        data: dict
             The element parameters presented as a dictionary.
+
         Examples
         --------
         >>> # Example using BearingElement
@@ -213,12 +216,14 @@ class Element(ABC):
     @staticmethod
     def dump_data(data, file_name):
         """Dumps element data in a toml file.
+
         Parameters
         ----------
         data: dict
             The data that should be dumped.
         file_name: string
             The name of the file the data will be dumped in.
+
         Returns
         -------
 
@@ -237,14 +242,15 @@ class Element(ABC):
 
     @abstractmethod
     def dof_mapping(self):
-        """Should return a dictionary with a mapping between degree of freedom
+        """Degrees of freedom mapping.
+
+        Should return a dictionary with a mapping between degree of freedom
         and its index.
-        Parameters
-        ----------
 
         Returns
         -------
-        A dictionary of degrees of freedom.
+        dof_mapping: dict
+            A dictionary containing the degrees of freedom and their indexes.
 
         Examples
         --------
@@ -258,12 +264,11 @@ class Element(ABC):
 
     def dof_local_index(self):
         """Get the local index for a element specific degree of freedom.
-        Parameters
-        ----------
 
         Returns
         -------
-        A named tuple containing the local index.
+        local_index: namedtupple
+            A named tuple containing the local index.
 
         Examples
         --------
@@ -281,12 +286,11 @@ class Element(ABC):
 
     def dof_global_index(self):
         """Get the global index for a element specific degree of freedom.
-        Parameters
-        ----------
 
         Returns
         -------
-        A named tuple containing the global index.
+        global_index: namedtupple
+            A named tuple containing the global index.
 
         Examples
         --------
diff --git a/ross/results.py b/ross/results.py
index dab36428..15da6eb2 100644
--- a/ross/results.py
+++ b/ross/results.py
@@ -203,7 +203,7 @@ class ModalResults:
     def kappa(self, node, w, wd=True):
         r"""Calculates kappa for a given node and natural frequency.
 
-        w is the the index of the natural frequency of interest.
+        frequency is the the index of the natural frequency of interest.
         The function calculates the orbit parameter :math:`\kappa`:
 
         .. math::
@@ -1996,7 +1996,9 @@ class SummaryResults:
         Bokeh WidgetBox with the summary table plot
     """
 
-    def __init__(self, df_shaft, df_disks, df_bearings, nodes_pos, brg_forces, CG, Ip, tag):
+    def __init__(
+        self, df_shaft, df_disks, df_bearings, nodes_pos, brg_forces, CG, Ip, tag
+    ):
         self.df_shaft = df_shaft
         self.df_disks = df_disks
         self.df_bearings = df_bearings
@@ -2060,7 +2062,7 @@ class SummaryResults:
             tags=self.df_bearings["tag"],
             brg_node=self.df_bearings["n"],
             brg_pos=self.nodes_pos[self.df_bearings["n"]],
-            brg_force=self.brg_forces
+            brg_force=self.brg_forces,
         )
 
         shaft_source = ColumnDataSource(shaft_data)
diff --git a/ross/rotor_assembly.py b/ross/rotor_assembly.py
index 131bc94d..5c4866b1 100644
--- a/ross/rotor_assembly.py
+++ b/ross/rotor_assembly.py
@@ -334,8 +334,12 @@ class Rotor(object):
         self.m = self.m_disks + self.m_shaft
 
         # rotor center of mass and total inertia
-        CG_sh = np.sum([(sh.m * sh.axial_cg_pos) / self.m for sh in self.shaft_elements])
-        CG_dsk = np.sum([disk.m * nodes_pos[disk.n] / self.m for disk in self.disk_elements])
+        CG_sh = np.sum(
+            [(sh.m * sh.axial_cg_pos) / self.m for sh in self.shaft_elements]
+        )
+        CG_dsk = np.sum(
+            [disk.m * nodes_pos[disk.n] / self.m for disk in self.disk_elements]
+        )
         self.CG = CG_sh + CG_dsk
 
         Ip_sh = np.sum([sh.Im for sh in self.shaft_elements])
@@ -407,18 +411,41 @@ class Rotor(object):
             dfb_z_pos = dfb[dfb.nodes_pos_l == z_pos]
             dfb_z_pos = dfb_z_pos.sort_values(by="n_l")
             if z_pos == df_shaft["nodes_pos_l"].iloc[0]:
-                y_pos = max(
-                    df_shaft["o_d_l"][df_shaft.n_l == int(dfb_z_pos.iloc[0]["n_l"])].values
-                ) / 2
+                y_pos = (
+                    max(
+                        df_shaft["o_d_l"][
+                            df_shaft.n_l == int(dfb_z_pos.iloc[0]["n_l"])
+                        ].values
+                    )
+                    / 2
+                )
             elif z_pos == df_shaft["nodes_pos_r"].iloc[-1]:
-                y_pos = max(
-                    df_shaft["o_d_r"][df_shaft.n_r == int(dfb_z_pos.iloc[0]["n_r"])].values
-                ) / 2
+                y_pos = (
+                    max(
+                        df_shaft["o_d_r"][
+                            df_shaft.n_r == int(dfb_z_pos.iloc[0]["n_r"])
+                        ].values
+                    )
+                    / 2
+                )
             else:
-                y_pos = max([
-                    max(df_shaft["o_d_l"][df_shaft._n == int(dfb_z_pos.iloc[0]["n_l"])].values),
-                    max(df_shaft["o_d_r"][df_shaft._n == int(dfb_z_pos.iloc[0]["n_l"]) - 1].values)
-                ]) / 2
+                y_pos = (
+                    max(
+                        [
+                            max(
+                                df_shaft["o_d_l"][
+                                    df_shaft._n == int(dfb_z_pos.iloc[0]["n_l"])
+                                ].values
+                            ),
+                            max(
+                                df_shaft["o_d_r"][
+                                    df_shaft._n == int(dfb_z_pos.iloc[0]["n_l"]) - 1
+                                ].values
+                            ),
+                        ]
+                    )
+                    / 2
+                )
             mean_od = np.mean(nodes_o_d)
             for t in dfb_z_pos.tag:
                 df.loc[df.tag == t, "y_pos"] = y_pos
@@ -949,7 +976,7 @@ class Rotor(object):
         frequency : float, optional
             Excitation frequency. Default is rotor speed.
         speed : float, optional
-            Rotating speed. Default is rotor speed (w).
+            Rotating speed. Default is rotor speed (frequency).
         modes : list, optional
             List with modes used to calculate the matrix.
             (all modes will be used if a list is not given).
@@ -1635,8 +1662,8 @@ class Rotor(object):
         ... )
         >>> stfx = [1e6, 2e7, 3e8]
         >>> stfy = [0.8e6, 1.6e7, 2.4e8]
-        >>> bearing0 = BearingElement(0, kxx=stfx, kyy=stfy, cxx=0, w=[0,1000, 2000])
-        >>> bearing1 = BearingElement(6, kxx=stfx, kyy=stfy, cxx=0, w=[0,1000, 2000])
+        >>> bearing0 = BearingElement(0, kxx=stfx, kyy=stfy, cxx=0, frequency=[0,1000, 2000])
+        >>> bearing1 = BearingElement(6, kxx=stfx, kyy=stfy, cxx=0, frequency=[0,1000, 2000])
         >>> rotor = Rotor(shaft_elem, [disk0, disk1], [bearing0, bearing1])
         >>> rotor.plot_ucs() # doctest: +ELLIPSIS
         <matplotlib.axes._subplots.AxesSubplot ...
@@ -1677,8 +1704,8 @@ class Rotor(object):
         bearing0 = bearings_elements[0]
 
         ax.plot(
-            bearing0.kxx.interpolated(bearing0.w),
-            bearing0.w,
+            bearing0.kxx.interpolated(bearing0.frequency),
+            bearing0.frequency,
             marker="o",
             color="k",
             alpha=0.25,
@@ -1687,8 +1714,8 @@ class Rotor(object):
             label="kxx",
         )
         ax.plot(
-            bearing0.kyy.interpolated(bearing0.w),
-            bearing0.w,
+            bearing0.kyy.interpolated(bearing0.frequency),
+            bearing0.frequency,
             marker="s",
             color="k",
             alpha=0.25,
@@ -1718,16 +1745,16 @@ class Rotor(object):
 
         # bokeh plot - plot shaft centerline
         bk_ax.circle(
-            bearing0.kxx.interpolated(bearing0.w),
-            bearing0.w,
+            bearing0.kxx.interpolated(bearing0.frequency),
+            bearing0.frequency,
             size=5,
             fill_alpha=0.5,
             fill_color=bokeh_colors[0],
             legend="Kxx",
         )
         bk_ax.square(
-            bearing0.kyy.interpolated(bearing0.w),
-            bearing0.w,
+            bearing0.kyy.interpolated(bearing0.frequency),
+            bearing0.frequency,
             size=5,
             fill_alpha=0.5,
             fill_color=bokeh_colors[0],
@@ -2236,14 +2263,14 @@ class Rotor(object):
         self.run_static()
         forces = self.bearing_reaction_forces
         results = SummaryResults(
-                self.df_shaft,
-                self.df_disks,
-                self.df_bearings,
-                self.nodes_pos,
-                forces,
-                self.CG,
-                self.Ip,
-                self.tag
+            self.df_shaft,
+            self.df_disks,
+            self.df_bearings,
+            self.nodes_pos,
+            forces,
+            self.CG,
+            self.Ip,
+            self.tag,
         )
         return results
 
@@ -2259,7 +2286,7 @@ class Rotor(object):
         min_w=None,
         max_w=None,
         n_eigen=12,
-        w=0,
+        frequency=0,
         nel_r=1,
     ):
 
@@ -2312,7 +2339,7 @@ class Rotor(object):
         ...                        DiskElement.from_geometry(n=2, material=steel, width=0.07, i_d=0, o_d=0.35)],
         ...             brg_seal_data=[BearingElement(n=0, kxx=1e6, cxx=0, kyy=1e6, cyy=0, kxy=0, cxy=0, kyx=0, cyx=0),
         ...                            BearingElement(n=3, kxx=1e6, cxx=0, kyy=1e6, cyy=0, kxy=0, cxy=0, kyx=0, cyx=0)],
-        ...             w=0, nel_r=1)
+        ...             frequency=0, nel_r=1)
         >>> modal = rotor.run_modal(speed=0)
         >>> modal.wn.round(4)
         array([ 85.7634,  85.7634, 271.9326, 271.9326, 718.58  , 718.58  ])
diff --git a/ross/shaft_element.py b/ross/shaft_element.py
index 95eed848..64428df6 100644
--- a/ross/shaft_element.py
+++ b/ross/shaft_element.py
@@ -23,9 +23,13 @@ class ShaftElement(Element):
     account shear, rotary inertia an gyroscopic effects.
     The matrices will be defined considering the following local
     coordinate vector:
-    .. math:: [x_0, y_0, \alpha_0, \beta_0, x_1, y_1, \alpha_1, \beta_1]^T
-    Where :math:`\alpha_0` and :math:`\alpha_1` are the bending on the yz plane and
-    :math:`\beta_0` and :math:`\beta_1` are the bending on the xz plane.
+
+    .. math::
+
+        [x_0, y_0, \alpha_0, \beta_0, x_1, y_1, \alpha_1, \beta_1]^T
+    Where :math:`\alpha_0` and :math:`\alpha_1` are the bending on the yz plane
+    and :math:`\beta_0` and :math:`\beta_1` are the bending on the xz plane.
+
     Parameters
     ----------
     L : float
@@ -57,8 +61,10 @@ class ShaftElement(Element):
     shear_method_calc : string, optional
         Determines which shear calculation method the user will adopt
         Default is 'cowper'
+
     Returns
     -------
+
     Attributes
     ----------
     Poisson : float
@@ -67,14 +73,17 @@ class ShaftElement(Element):
         Element section area.
     Ie : float
         Ie is the second moment of area of the cross section about
-        the neutral plane Ie = pi*r**2/4
+        the neutral plane :math:`Ie = \pi r^2/4`
     phi : float
-        Constant that is used according to [1]_ to consider rotary
-        inertia and shear effects. If these are not considered phi=0.
+        Constant that is used according to :cite:`friswell2010dynamics` to
+        consider rotary inertia and shear effects. If these are not considered
+        :math:`\phi=0`.
+
     References
     ----------
-    .. [1] 'Dynamics of Rotating Machinery' by MI Friswell, JET Penny, SD Garvey
-       & AW Lees, published by Cambridge University Press, 2010 pp. 158-166.
+
+    .. bibliography:: ../../../docs/refs.bib
+
     Examples
     --------
     >>> from ross.materials import steel
@@ -298,9 +307,12 @@ class ShaftElement(Element):
     @classmethod
     def from_table(cls, file, sheet_type="Simple", sheet_name=0):
         """Instantiate one or more shafts using inputs from an Excel table.
-        A header with the names of the columns is required. These names should match the names expected by the routine
-        (usually the names of the parameters, but also similar ones). The program will read every row bellow the header
-        until they end or it reaches a NaN.
+
+        A header with the names of the columns is required. These names should
+        match the names expected by the routine (usually the names of the
+        parameters, but also similar ones). The program will read every row
+        bellow the header until they end or it reaches a NaN.
+
         Parameters
         ----------
         file: str
@@ -314,9 +326,10 @@ class ShaftElement(Element):
         sheet_name: int or str, optional
             Position of the sheet in the file (starting from 0) or its name. If none is passed, it is
             assumed to be the first sheet in the file.
+
         Returns
         -------
-        shaft : list
+        shaft: list
             A list of shaft objects.
         """
         parameters = read_table_file(
@@ -468,9 +481,12 @@ class ShaftElement(Element):
 
     def M(self):
         r"""Mass matrix for an instance of a shaft element.
+
         Returns
         -------
-        Mass matrix for the shaft element.
+        M: np.ndarray
+            Mass matrix for the shaft element.
+
         Examples
         --------
         >>> Timoshenko_Element = ShaftElement(0.25, 0, 0.05, steel,
@@ -525,9 +541,12 @@ class ShaftElement(Element):
 
     def K(self):
         r"""Stiffness matrix for an instance of a shaft element.
+
         Returns
         -------
-        Stiffness matrix for the shaft element.
+        K: np.ndarray
+            Stiffness matrix for the shaft element.
+
         Examples
         --------
         >>> from ross.materials import steel
@@ -559,15 +578,25 @@ class ShaftElement(Element):
         return K
 
     def C(self):
-        """Stiffness matrix for an instance of a shaft element.
+        """Damping matrix for an instance of a shaft element.
 
         Returns
         -------
-        C : np.array
+        C: np.ndarray
            Damping matrix for the shaft element.
 
         Examples
         --------
+        >>> from ross.materials import steel
+        >>> # Timoshenko is the default shaft element
+        >>> Timoshenko_Element = ShaftElement(0.25, 0, 0.05, steel)
+        >>> # Currently internal damping for the shaft elements is not
+        >>> # considered, so the matrix has only zeros.
+        >>> Timoshenko_Element.C()[:4, :4]
+        array([[0., 0., 0., 0.],
+               [0., 0., 0., 0.],
+               [0., 0., 0., 0.],
+               [0., 0., 0., 0.]])
         """
         C = np.zeros((8, 8))
 
@@ -575,9 +604,12 @@ class ShaftElement(Element):
 
     def G(self):
         """Gyroscopic matrix for an instance of a shaft element.
+
         Returns
         -------
-        Gyroscopic matrix for the shaft element.
+        G: np.ndarray
+            Gyroscopic matrix for the shaft element.
+
         Examples
         --------
         >>> from ross.materials import steel
@@ -615,7 +647,9 @@ class ShaftElement(Element):
 
     def patch(self, position, check_sld, ax):
         """Shaft element patch.
+
         Patch that will be used to draw the shaft element.
+
         Parameters
         ----------
         position : float
@@ -624,8 +658,10 @@ class ShaftElement(Element):
             If True, HoverTool displays only the slenderness ratio
         ax : matplotlib axes, optional
             Axes in which the plot will be drawn.
+
         Returns
         -------
+
         """
         position_u = [position, self.i_d / 2]  # upper
         position_l = [position, -self.o_d / 2]  # lower
@@ -668,7 +704,9 @@ class ShaftElement(Element):
 
     def bokeh_patch(self, position, check_sld, bk_ax):
         """Shaft element patch.
+
         Patch that will be used to draw the shaft element.
+
         Parameters
         ----------
         position : float
@@ -677,9 +715,10 @@ class ShaftElement(Element):
             If True, HoverTool displays only the slenderness ratio
         bk_ax : bokeh plotting axes, optional
             Axes in which the plot will be drawn.
+
         Returns
         -------
-        hover : Bokeh HoverTool
+        hover: Bokeh HoverTool
             Bokeh HoverTool axes
         """
         if check_sld is True and self.slenderness_ratio < 1.6:
@@ -784,8 +823,10 @@ class ShaftElement(Element):
         gyroscopic=True,
     ):
         """Shaft section constructor.
-        This method will create a shaft section with length 'L'
-        divided into 'ne' elements.
+
+        This method will create a shaft section with length 'L' divided into
+        'ne' elements.
+
         Parameters
         ----------
         i_d : float
@@ -816,10 +857,12 @@ class ShaftElement(Element):
         gyroscopic : bool
             Determine if gyroscopic effects are taken into account.
             Default is False.
+
         Returns
         -------
         elements: list
             List with the 'ne' shaft elements.
+
         Examples
         --------
         >>> # shaft material
diff --git a/ross/utils.py b/ross/utils.py
index d681709c..efa7dc77 100644
--- a/ross/utils.py
+++ b/ross/utils.py
@@ -57,14 +57,14 @@ def read_table_file(file, element, sheet_name=0, n=0, sheet_type="Model"):
         optional_parameter_columns["cyy"] = ["cyy"]
         optional_parameter_columns["cxy"] = ["cxy"]
         optional_parameter_columns["cyx"] = ["cyx"]
-        optional_parameter_columns["w"] = ["w", "speed"]
+        optional_parameter_columns["frequency"] = ["frequency", "speed"]
         default_dictionary["kyy"] = None
         default_dictionary["kxy"] = 0
         default_dictionary["kyx"] = 0
         default_dictionary["cyy"] = None
         default_dictionary["cxy"] = 0
         default_dictionary["cyx"] = 0
-        default_dictionary["w"] = None
+        default_dictionary["frequency"] = None
     elif element == "shaft":
         if sheet_type == "Model":
             header_key_word = "od_left"
@@ -275,7 +275,9 @@ def read_table_file(file, element, sheet_name=0, n=0, sheet_type="Model"):
     if convert_to_rad_per_sec:
         for i in range(0, df.shape[0]):
             if element == "bearing":
-                parameters["w"][i] = parameters["w"][i] * 0.104_719_755_119_7
+                parameters["frequency"][i] = (
+                    parameters["frequency"][i] * 0.104_719_755_119_7
+                )
     parameters.update(new_materials)
     return parameters
 
diff --git a/setup.py b/setup.py
index feb97b45..945a326c 100644
--- a/setup.py
+++ b/setup.py
@@ -61,6 +61,7 @@ EXTRAS = {
         "sphinx_bootstrap_theme",
         "nbsphinx",
         "numpydoc",
+        "sphinxcontrib-bibtex",
     ]
 }
 


Test patch:
diff --git a/ross/tests/test_bearing_seal_element.py b/ross/tests/test_bearing_seal_element.py
index c248e2b3..1c789a47 100644
--- a/ross/tests/test_bearing_seal_element.py
+++ b/ross/tests/test_bearing_seal_element.py
@@ -27,7 +27,12 @@ def bearing0():
     )
     wb = np.array([314.2, 418.9, 523.6, 628.3, 733.0, 837.8, 942.5, 1047.2, 1151.9])
     bearing0 = BearingElement(
-        4, kxx=Kxx_bearing, kyy=Kyy_bearing, cxx=Cxx_bearing, cyy=Cyy_bearing, w=wb
+        4,
+        kxx=Kxx_bearing,
+        kyy=Kyy_bearing,
+        cxx=Cxx_bearing,
+        cyy=Cyy_bearing,
+        frequency=wb,
     )
     return bearing0
 
@@ -77,7 +82,12 @@ def bearing1():
     )
     wb = [314.2, 418.9, 523.6, 628.3, 733.0, 837.8, 942.5, 1047.2, 1151.9]
     bearing1 = BearingElement(
-        4, kxx=Kxx_bearing, kyy=Kyy_bearing, cxx=Cxx_bearing, cyy=Cyy_bearing, w=wb
+        4,
+        kxx=Kxx_bearing,
+        kyy=Kyy_bearing,
+        cxx=Cxx_bearing,
+        cyy=Cyy_bearing,
+        frequency=wb,
     )
     return bearing1
 
@@ -129,24 +139,27 @@ def test_bearing_error_speed_not_given():
     cx = 1e8 * speed
     with pytest.raises(Exception) as excinfo:
         BearingElement(-1, kxx=kx, cxx=cx)
-    assert "Arguments (coefficients and w)" " must have the same dimension" in str(
-        excinfo.value
+    assert (
+        "Arguments (coefficients and frequency)"
+        " must have the same dimension" in str(excinfo.value)
     )
 
 
 def test_bearing_error2():
     with pytest.raises(ValueError) as excinfo:
         BearingElement(
-            4, kxx=[7e8, 8e8, 9e8], cxx=[0, 0, 0, 0], w=[10, 100, 1000, 10000]
+            4, kxx=[7e8, 8e8, 9e8], cxx=[0, 0, 0, 0], frequency=[10, 100, 1000, 10000]
         )
-    assert "Arguments (coefficients and w) " "must have the same dimension" in str(
-        excinfo.value
+    assert (
+        "Arguments (coefficients and frequency) "
+        "must have the same dimension" in str(excinfo.value)
     )
 
     with pytest.raises(ValueError) as excinfo:
         BearingElement(4, kxx=[6e8, 7e8, 8e8, 9e8], cxx=[0, 0, 0, 0, 0])
-    assert "Arguments (coefficients and w) " "must have the same dimension" in str(
-        excinfo.value
+    assert (
+        "Arguments (coefficients and frequency) "
+        "must have the same dimension" in str(excinfo.value)
     )
 
 
@@ -172,7 +185,7 @@ def test_bearing_len_2():
         cyy=[3.13, 10.81],
         cxy=[0.276, 0.69],
         cyx=[-0.276, -0.69],
-        w=[115.19, 345.575],
+        frequency=[115.19, 345.575],
     )
     assert_allclose(bearing.kxx.interpolated(115.19), 481, rtol=1e5)
 
@@ -188,7 +201,7 @@ def test_bearing_len_3():
         cyy=[3.13, 10.81, 22.99],
         cxy=[0.276, 0.69, 1.19],
         cyx=[-0.276, -0.69, -1.19],
-        w=[115.19, 345.575, 691.15],
+        frequency=[115.19, 345.575, 691.15],
     )
     assert_allclose(bearing.kxx.interpolated(115.19), 481, rtol=1e5)
 
diff --git a/ross/tests/test_examples.py b/ross/tests/test_examples.py
index 3549a27e..bbf3fa44 100644
--- a/ross/tests/test_examples.py
+++ b/ross/tests/test_examples.py
@@ -13,7 +13,7 @@ def rotor_example1(n_el=48):
 
     P.S.:Isotropic bearings.
 
-    :param w: speed of rotation.
+    :param frequency: speed of rotation.
     :param n_el: number of shaft elements.
     :return: Rotor object.
     """
diff --git a/ross/tests/test_rotor_assembly.py b/ross/tests/test_rotor_assembly.py
index 4b04c4b9..f0c3a9df 100644
--- a/ross/tests/test_rotor_assembly.py
+++ b/ross/tests/test_rotor_assembly.py
@@ -961,7 +961,7 @@ def test_from_section():
         i_ds_data=i_ds_data,
         disk_data=disk_data,
         brg_seal_data=brg_seal_data,
-        w=0,
+        frequency=0,
         nel_r=4,
     )
 
@@ -983,7 +983,7 @@ def test_from_section():
             i_ds_data=i_ds_data,
             disk_data=disk_data,
             brg_seal_data=brg_seal_data,
-            w=0,
+            frequency=0,
             nel_r=4,
         )
     assert "The matrices lenght do not match." == str(excinfo.value)
@@ -995,7 +995,7 @@ def test_from_section():
             i_ds_data=i_ds_data,
             disk_data=disk_data,
             brg_seal_data=brg_seal_data,
-            w=0,
+            frequency=0,
             nel_r=4,
         )
     assert "The matrices lenght do not match." == str(excinfo.value)