Links to pages on the web:
http://www.cypripedium.de/ the homepage of Michael Weinert, a very interessting Cypripediums Forum (in English) and plenty of information about Cypripedium hybrids. New is a guide to division of Cypripediums with images: How to divide Cypripediums
http://www.w-frosch.de/index.html The breeder Werner Frosch, hybrid list, a lot about Cypripediums, photos of all the hybrids and natural forms.
http://www.orchidee.de German Orchid Society
http://www.fh-friedberg.de/allgemein/ahohompg/ahogerm.htm workgroups Native Orchids
Last but not least, a link of our own: On my website under www.garten-orch-ideen.de there are always new information on Cypripedium hybrids and companion plants.