a NOVA production by the New York Times/Granada Factuals USA and Lone Wolf Pictures, Inc., for WGBH/Boston in association with Channel 4 ; directed by Kirk Wolfinger ; produced & written by Matthew Collins
a co-production of the WGBH/NOVA Science Unit and Clear Blue Sky Productions ; written by Joel Olicker and Chris Schmidt ; produced and directed by Joel Olicker
a co-production of the WGBH/NOVA Science Unit and Clear Blue Sky Productions ; written by John Heminway, produced by John Heminway & Michelle Nicholasen