a Nova/WGBH, La Cinquième, Südwestrundfunk, Gedéon Programmes, Meridian, and NHK co-production ; produced for Nova by Providence Pictures, Inc. for WGBH/Boston ; written and directed by Liesl Clark
a WGBH Science Unit Production by Debonair Production Company in association with La Cinquiéme ; WGBH Educational Foundation ; produced and directed by David Espar, Diane Hendrix & Michael Rossiter