a Blakeway Production for the BBC and WGBH Boston ; produced by Chris Oxley & Malcolm Neum ; directed by Chis Oxley ; produced for NOVA by Joseph McMaster ; narration written by Joseph McMaster
a Nova production by Green Umbrella Ltd. for WGBH/Boston in association with BBC-TV and Sveriges Television ; produced by Peter Jones and Thomas Levenson ; written by Thomas Levenson ; directed by Peter Jones