Encyclopaedia Britannica Educational Corporation ; a production for the Open University ; BBC ; in association with Penn State, Division of Media and Learning Resources ; produced by Rissa De La Paz
Films for the Humanities presentation ; Granada Television International ; made with the cooperation of the Wildfowl Trust, California Institute of Technology ; written by Michael Dearden and Jack Smith ; produced and directed by Jack Smith ; made in association with Norddeutscher Rundfunk
M.R. Clarke, K.M. Phillippi, J.A. Falkenstein, E.A. Moran, Delta Regional Primate Research Center, and S.J. Suomi, Laboratory Comparative Ethology, NICHD