CiteSeer

CiteSeer was a public search engine and digital library for scientific and academic papers, primarily in the fields of computer and information science that has been replaced by CiteSeer^X. Many consider it to be the first academic paper search engine. It became public in 1998 and had many new features unavailable in academic search engines at that time. These included:

• Autonomous Citation Indexing automatically created a citation index that can be used for literature search and evaluation.
• Citation statistics and related documents were computed for all articles cited in the database, not just the indexed articles.
• Reference linking allowing browsing of the database using citation links.
• Citation context showed the context of citations to a given paper, allowing a researcher to quickly and easily see what other researchers have to say about an article of interest.
• Related documents were shown using citation and word based measures and an active and continuously updated bibliography is shown for each document.