Below are the resources commonly used in a patent search. All are available in paper or on cd-rom at Patent and Trademark Depository Libraries . Several of these titles are available on the Web . See patent searching for instructions on how to use these resources. Index to U.S. Classification - the Index is a bridge between common terms used to describe an invention and the specific terminology used by the US Patent and Trademark Office listed in the Manual of Classification.
Every patent is assigned an original classification and several cross-reference classifications.
Available online SunSite from the University of North Carolina at Chapel Hill Manual of Classification - the Manual is the complete listing of classes and their subclasses, arranged by class number in ascending order. Patents Class - lists patents issued since 1790 by classification number. Patents Bib - lists utility patents issued since 1969 by classification number. Lists plant and design patents issued since 1975 by classification number. Official Gazette - contains brief description of patents, one claim and one drawing included for each patent.