Map version

Economists Online

http://www.nereus4economics.info/neeo.html 

A service developed by the NEEO (Network of European Economists Online) EU-funded project. Harvests from 18 university partner institutions and RePEc.

INSPIRE

http://www.interactions.org/cms/?pid=1026243 

Collaboration of CERN, DESY, Fermilab and SLAC. To deliver OA full-texts across the whole HEP literature using Invenio digital library platform (CERN). Unifying SPIRES, arXiv, ADS, etc with a common interface. Features to include full-text Google-like searching and enablement of text- and data-mining applications.

CiteSeer

http://citeseerx.ist.psu.edu/about/site;jsessionid=E9E6FFD23B6B5F01F9D8EDD1FE54EC70 

Computer and information science collection hosted at Pennsylvania State University. Originally established in 1997. Harvests content from the Web and provides automatic citation indexing and linking using 'autonomous citation indexing' method.

RePEc

http://repec.org/ 

Metadata harvester for economics. Harvests from hundreds of archives around the world.