Department of Vertebrate Zoology, National Museum of Natural History. The Passenger Pigeon. Encyclopedia Smithsonian. Smithsonian Institution. March 2001 [April 22, 2013]. (原始内容存档于March 13, 2012).
Department of Vertebrate Zoology, National Museum of Natural History. The Passenger Pigeon. Encyclopedia Smithsonian. Smithsonian Institution. March 2001 [April 22, 2013]. (原始内容存档于March 13, 2012).