Não informado. (1940). Special Scientific Report. U.S. Fish and Wildlife Service.
Chicago-viite (17. p.)Não informado. Special Scientific Report. Seattle, Wash: U.S. Fish and Wildlife Service, 1940.
MLA-viite (8. p.)Não informado. Special Scientific Report. U.S. Fish and Wildlife Service, 1940.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.