1. Untersuchen zur Tiersoziologie, insebesondere zur Auflösung der Familie;Brückner;Z. Psychol,1923
2. The development of social behavior in birds;Collias;Auk,1952
3. Social life and the individual among vertebrate animals;Collias;Ann. N.Y. Acad. Sci,1950
4. Zur Ethologie junger Anatiden;Fabricius;Acta Zool. Fenn,1951
5. Experiments on the following reactions of ducklings;Fabricius;Wildfowl Trust Annual Report,1954