Most patents provide a list of “Cited References,” which includes citations added to the patent during the examination process. In addition, most of the modern patent databases also link the references that are citing a particular patent document, under “Citing References.” These citations of a patent/application are also known as backward citations and forward citations, respectively.

These citations may have been added either by the examiner or provided by the applicant in the Invention Disclosure Form and are often related to similar technologies as the area of the concerned patent.  Patent Citations can come in multiple forms, including US Patents, Foreign Patents, Search Reports, and Non-Patent Literature.  The lists of the cited references are usually found on the cover page of a patent document.  Further, one may look into the Prosecution History to find the search strategy of the examiner and also any other document that may have been cited during examination, but may have been missed and not included on the cover page as “cited reference.”

The references listed under the “cited references” and “citing references” gives a researcher, who may be involved in a prior-art search, an automatic head-start on the research process.  These references can be used as a start to learn about the technology area of the patent as these documents contain basic and related information about the technology. If one may use the available information correctly, the cited references can often provide important leads.  For example, by examining the cited patents, one may discover relevant classifications, active inventors/applicants and other industries that may be useful to find relevant references in a prior-art search.  Making these connections can greatly increase the breadth of search and this information could be used to find even more relevant prior art. Further, these citations may be used as a standard against which the found references may be assessed.

Further, these references can be analyzed to identify a technology trend in a particular field of technology. Analysis of patent citations may also help in assessing commercial value of patents, as with the patent having high number of forward citations may disclose technology which have been later used by many other inventors. Furthermore, in some cases, cited patents may have been involved in litigation; and any prior litigation charges can provide clues around prior uses for the technology.