Citebase Search was an experimental, semi-autonomous citation index for free, online research literature created at the University of Southampton as part of the Open Citation Project. It harvested open access e-prints (most author self-archived) from OAI-PMH compliant archives, parses and links their references and indexes the metadata in a Xapian-based search engine. Citebase went live in 2005 and ceased operation in 2013. More than three-quarters of the papers indexed were author self-archived in the ArXiv archive, which includes physics, maths and computer science. Some (published) biomedical papers were indexed from BioMed Central and PubMed Central. See also EPrints Citeseer NASA ADS Stanford Physics Information Retrieval System References External links Archive of last available version of citebase home page (December 2012) Internet search engines Bibliographic databases and indexes Scholarly search services