ISBN 0-19-854012-4* Peterson, Roger Tory; Peterson, Virginia Marie; National Audubon Society; National Wildlife Federation & Roger Tory Peterson Institute (1990): "A field guide to western birds: a completely new guide to field marks of all species found in North America west of the 100th meridian and north of Mexico".
ISBN 0-19-854012-4* Peterson, Roger Tory; Peterson, Virginia Marie; National Audubon Society; National Wildlife Federation & Roger Tory Peterson Institute (1990): "A field guide to western birds: a completely new guide to field marks of all species found in North America west of the 100th meridian and north of Mexico".