LINE (University of Central Florida)
http://library.ucf.edu/line/

Michigan Information Transfer Source (MITS)
http://www.lib.umich.edu/mits/

Netherlands Institute for Scientific Information Services (NIWI)
http://www.niwi.knaw.nl/us/homepag.htm

PLUS Information Service (University California, San Diego)
http://gort.ucsd.edu/capplus/plus.html

Speedy Research Service
http://galis.org/srs