The tracking of how scholars cite each others' work over time is what we mean by citation searching and tracking.
Citations can be traced through the use of several tools that are available on the market.
The three primary tools are Web of Knowledge, Scopus and Google Scholar.
The citation indexes are strongest in the sciences with Scopus including over 12,000 science and medicine titles and Science Citation Index over 6,100 titles. Coverage in other fields is markedly less comprehensive. In the social sciences Scopus covers around 2,700 titles and Social Sciences Citation Index covers around 1,700 titles. Arts & Humanities Citation Index includes approximately 1,300 publications and is the only tool for tracking citations in those fields.
Google Scholar is another useful option for citation search, but one that is an anomaly in the
library profession. While it tracks citations for articles from both books and articles,
Google does not share the list of what vendors are involved in the project and so librarians cannot tell with any certainty just what it is searching.
Links to articles about Google Scholar's coverage: