# LaTeX/Bibliographies with biblatex and biber

Learn how to create a bibliography using modern biblatex and biber - A short tutorial.
This will only be a short overview of the main and most often used features of biblatex and biber to create a bibliography.
More detailed information can be found in the package documentation.

### The database

Creating a bibliography using biblatex and biber means storing all of your available bibliographic information in a simple text-based database. The name should be as unique as possible, for example lauraPhd2016.bib. This is helpful when transferring files with your advisor, students or colleagues. biber is used to deal with the database.
A sample database file could look like this:
Every entry in the database starts with an @-sign followed by the entry type. More types are available, the package documentation lists all of them. The bibliographic information for each entry are stored in a pair of braces, beginning with a unique keyword for that entry (bibkey). Least complicated way of presenting the data is every field type in a new line, the content in curly braces, followed by a comma. The order in which you give the information is not important.
Please have a close look at the authors, every individual author is separated by the keyword and. All dates are written in YYYY-MM-DD, or just the year if the other information is not available. The file biblatex-examples.bib which should have been installed with the package contains some sample entries.

### Setting up biber

Biber is the name of the helper program that sorts the entries and provides all the relevant information to package biblatex. If you are not comfortable using the command line (aka the terminal), you should set up your editor to call biber for you. Setting up my editor to use biber shows how to do it for the different editors.

### A simple example

* \documentclass{article}
* \usepackage[backend=biber]{biblatex}
* \addbibresource{lauraPhd2016.bib}
* \begin{document}
* I doubt that there is any useful information here~\cite{wikibook}.
* All we know is limited, apart from knowing the answer we all know. Or do we? Wombat and Koala have discovered some interesting things~\cite{wombat2016}.
* Some people are too nosy. What can happen to them is described by Laura Lion~\cite[9]{lion2010}.
* \printbibliography
* \end{document}
Now how does it actually work? Package biblatex is loaded with the option backend=biber followed by adding your database file to the list of bibliographic files using \addbibresource. Please note that the file extension is mandatory and that this is happening in the preamble of the document.
Within the document you can cite one of your database entries using \cite{bibkey}. Your database can contain hundreds of entries, but only cited references will occur in the final list. You can use \nocite{<bibkey>} to add uncited entries to the list. If you want to add all entries from the database use \nocite{*}.
Finally, the list of your references is printed with \printbibliography.
Running LaTeX (no matter if latex, pdflatex etc.) on the main document will result in the following log output.
We get several warnings about undefined references, no bibliography and instead of proper citations, we see just the cite key in bold.
In order to really get a bibliography and the citations, and not just the infamous There were undefined references warning, you have to run biber after latex to extract the relevant data from the database. After setting up biber as described in Setting up my editor to use biber you should be able to do it by pressing one button while working on your document. To incorporate the bibliography information into your document, LaTeX then has to process the data biber has generated before. To sum it up, if you have a file lauraPhd2016Main.tex you (or your editor) will have to do:
Everytime your database is updated, remember to process the database by calling biber.
The full result can be seen in the picture below. Please note that package biblatex adds some small little details. Can you see things that are printed but have not been defined?

## Reference Styles

Different reference styles are in use within the different disciplines of science. Very broadly speaking, you can divide into a numerical referencing system (Vancouver) or an author date referencing system (Harvard).
Package biblatex provides different citation commands that generate different output (in-text citation, footnotes and more). A few examples are given below, the package documentation contains and explains the use of the whole set.

### Numerical Referencing

Numerical referencing is the default style. Numbers within brackets are used in text and in the bibliography. Using \autocite makes it easy to change the style into footnotes. sorting=none gives a bibliography that is sorted chronologically, i.e. the numbers increase to the end of the document.
* \documentclass{article}
* \usepackage[backend=biber,style=numeric,autocite=plain,sorting=none]{biblatex}
* \addbibresource{lauraPhd2016.bib}
* \begin{document}
* I doubt that there is any useful information here.~\cite{wikibook}
* All we know is limited, apart from knowing the answer we all
* know. Or do we? \citeauthor{wombat2016} have discovered some interesting
* things.~\autocite[compare][80]{wombat2016}
* What can happen to nosy people is described by \textcite[9]{lion2010}.
* \printbibliography
* \end{document}
Using autocite=footnote gives a different output. Can you spot all the differences?

### Author Date Referencing

If you want an author-date referencing style, you can use style=authoryear when loading biblatex. The option autocite with the option inline puts parenthesis around the cite genererated with autocite (which is similar to using \parencite). In some cases, \textcite may come in handy when the citation is the subject and part of the sentence flow.
* \documentclass{article}
* \usepackage[backend=biber,style=authoryear,autocite=inline]{biblatex}
* \addbibresource{lauraPhd2016.bib}
* \begin{document}
* I doubt that there is any useful information here~\cite{wikibook}.
* All we know is limited, apart from knowing the answer we all know. Or do we?~\cite{wombat2016}
* Some people are too nosy. What can happen to them is described by Laura Lion~\autocite[9]{lion2010}.
* Some people are too nosy. What can happen to them is described by \textcite[9]{lion2010}.
* \printbibliography
* \end{document}

### APA Citing

The American Psychological Association (APA) defines a very strict author year style. You can access it using style=apa and additionally defining the language mapping.
* \usepackage[backend=biber,style=apa,autocite=inline]{biblatex}
* \DeclareLanguageMapping{english}{english-apa}
* \addbibresource{lauraPhd2016.bib}
Compare the output with the normal author year style. How many changes can you spot?

## Separate Bibliographies by Entry Type

Suppose you want to have a separate bibliography for all the online resources you are citing. No problem using the optional argument of \printbibliography. You can also change the title (and other stuff).
* \documentclass{article}
* \usepackage[backend=biber,defernumbers=true]{biblatex}
* \addbibresource{biblatex-examples.bib}
* \begin{document}
* \nocite{westfahl:space,aristotle:physics,ctan,baez/online,markey,sigfridsson}
* \printbibheading
* \printbibliography[heading=subbibliography,type=online,title={All my online references}]
* \printbibliography[heading=subbibliography,nottype=online,title={All my non-online references}]
* \end{document}

## Splitting into different topics

You can split your bibliography into different topics, in trusted and untrusted sources, or in primary and secondary sources. The way to tell biblatex what is what, is by adding a keywords tag to the entries of the database.
* \documentclass{article}
* \usepackage[backend=biber,style=authoryear,refsection=section]{biblatex}
* \addbibresource{lauraPhd2016.bib}
* \begin{document}
* \cites[see also][12]{wombat2016}[and][45]{lion2010}
* \nocite{wikibook}
* \printbibliography[keyword={trusted},title={All the trusted sources}]
* \printbibliography[keyword={untrusted},title={All the untrusted sources}]
* \end{document}
Note, that the entryfield in the database is called keywords (plural) because you can have more than one keyword (separated by commas). When calling the \printbibliography command, you have to use the singular. biblatex has a powerful system of filtering data, more can be found in the manual.

## Bibliographies per Section or Chapter

Some people have the need for a reference list at the end of each chapter or section. This can be done using refsection.
* \documentclass{article}
* \usepackage[backend=biber,defernumbers=true,refsection=section]{biblatex}
* \addbibresource{biblatex-examples.bib}
* \begin{document}
* \section{Aster}
* \cite{ctan,sigfridsson} and some text
* \printbibliography[heading=subbibliography]
* \section{Begonia}
* \cite{aristotle:physics,markey}
* \printbibliography[heading=subbibliography]
* \section{Cichorium}
* \cite{westfahl:space,baez/online}
* \printbibliography[heading=subbibliography]
* \end{document}

## A bibliography in a presentation

You can use package biblatex with beamer (see the Presentations section) to have citations and a reference list in your presentation. Using full cites right away is recommended, so listeners don't have to wait till the very end to see where information is drawn from.
* \documentclass{beamer}
* \usecolortheme{crane}
* \usepackage{biblatex}
* \addbibresource{lauraPhd2016.bib}
* \begin{document}
* \begin{frame}{42}
* Interesting
* \footfullcite{wombat2016}
* \end{frame}
* \nocite{*}
* \begin{frame}{References}
* \printbibliography
* \end{frame}
* \end{document}
* ↑ [biblatex on CTAN]
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