written and produced by Graham Chedd ; directed by Larry Engel ; a co-production of Chedd-Angier-Lewis Productions and Thirteen in association with WNET.ORG
a NOVA production by Erikson & Nilsson Production in association with WGBH/Boston ... [and others] ; medical photography, Lennart Nilsson ; produced, written by Julia Cort
by David Attenborough ; a BBC TV production in association with Australian Broadcasting Corporation, Turner Broadcasting System Inc. ; BBC Bristol ; executive producer, Peter Jones