FreeWAIS-sf is an extension of the freeWAIS software provided by the the 
Clearinghouse for Networked Information Discovery and  Retrieval (CNIDR). 
The SF suffix in the software name stands for  "structured fields," an 
indexing  and search feature which  distinguishes this software from its 
predecessors.

WWW: http://ls6-www.informatik.uni-dortmund.de/ir/projects/freeWAIS-sf/