Não informado. (2003). North American Birds. American Birding Association.
Chicago-referens (17:e uppl.)Não informado. North American Birds. Colorado Springs, Colo: American Birding Association, 2003.
MLA-referens (8:e uppl.)Não informado. North American Birds. American Birding Association, 2003.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.