OVID
Technologies
http://www.ovid.com
SILVERPLATTER
http://www.silverplatter.com
CAMBRIDGE
SCIENTIFIC ABSTRACTS
http://www.csa.com
RESEARCH
LIBRARIES GROUP RLG Eureka
http://www.rlg.com
INFORMATION
ACCESS COMPANY International Division
http://www.international.iacnet.com
ENGINEERING
INFORMATION INC.
http://www.ei.org
CHADWYCK-HEALEY
http://www.chadwyck.co.uk
UMI
- University Microfilm International
http://www.umi.com
ISI
- Institut for Scientific Information
http://www.isinet.com
H.W.WILSON
http://www.hwwilson.com