written, produced and directed by William Cran ; a Frontline coproduction with InVision Productions, Ltd. in association with BBC-2 ; WGBH Educational Foundation
produced by Furnace Limited for Thirteen in association with WNET.ORG, Channel 4, National Geographic Channel UK, ABC Australia, and ZDF ; written and directed by Richard Bond
produced by Michael Kirk, Jim Gilmore, Mike Wiser ; written by Michael Kirk & Mike Wiser ; directed by Michael Kirk ; a Frontline production with Kirk Documentary Group ; WGBH Educational Foundation ; a production of WGBH Boston