The Herd of Kittens - Library Tools

expat
James Clark's XML parser in C
Business-ISBN-1.0
brian d foy comdog@computerdog.com's ISBN handling perl code, useful for re-checksumming EAN's into ISBN's
isbn.el
Nelson H. F. Beebe's elisp code for handling ISBN's
YAZ
YAZ is the Z39.50 tookit from Index Data, Copenhagen (info@index.ping.dk)
mod_search.c
Apache search module that uses the YAZ Z39.50 toolkit to gateway http to Z39.50, as used by LoC and others
libwww-perl
Perl libraries for general web walking and web page manipulation, from http://www.linpro.no/lwp/.
flatbed upc software
http://www.adams1.com/pub/russadam/share.html
zeta perl
pure perl Z39.50 code