Peterson, R. T. (1961). A field guide to western birds: Field marks of all species found in North America west of the 100th meridian with a section on the birds of the Hawaiian Island (2a. ed.). Cambridge: Riberside.

Peterson, Roger Tory. A Field Guide to Western Birds: Field Marks of All Species Found in North America West of the 100th Meridian With a Section On the Birds of the Hawaiian Island. 2a. ed. Cambridge: Riberside, 1961.

Peterson, Roger Tory. A Field Guide to Western Birds: Field Marks of All Species Found in North America West of the 100th Meridian With a Section On the Birds of the Hawaiian Island. 2a. ed. Cambridge: Riberside, 1961.