CiteSeer is a scientific literature digital library and search engine that focuses primarily on the literature in computer and information science. CiteSeer aims to improve the dissemination and feedback of the scientific literature and to provide improvements in functionality, usability, availability, cost, comprehensiveness, efficiency, and timeliness in the access of scientific and scholarly knowledge.

MathSciNet is a comprehensive database covering the world's mathematical literature since 1940. It provides Web access to reviews, abstracts and bibliographic information from Mathematical Review and Current Mathematical Publications. The database contains information on over 4 million articles and books, with direct links to over 2.7 million articles in over 1,800 journals.