Some of these links are related to Spearfishing. If you - for any reason - have problems with this don't follow them.

Hans's Record Page Comprehensive Record Page by Hans Imwinkelried
A book on Freediving A book on freediving: How to freedive, apnea and
snorkel by Terry Maas
A.I.D.A. A.I.D.A. ( Association Internationale pour le Développement de l'Apnée)
Prevention of Middle Ear Barotrauma Excellent and comprehensive summary about prevention of middle ear barotrauma and several techniques for equalization
Freediving Internet Magazine Freediving Internet Magazin, contains information about Spearfishing
Umberto Pelizzari Web Site Homepage of Umberto Pelizzari. Information about Freediving, Records and Umberto
Pipin Productions Home Page Homepage of Pipin Productions with an interesting page about the history of freediving
Freedive List - The Site Page of the international freedive mailing list. Related to Freediving and Spearfishing
Omer Omer for Spearfishing, Technosport, Inc.