Pteroglossus bitorquatus bitorquatus - Red-necked Aracari

Riker, C. B. 1891. Auk: 8(2): 158-164.
A List of Birds Observed at Santarem, Brazil

Zimmer, J. T. and E. Mayr. 1943. Auk: 60(2): 249-262.
New Species of Birds Described from 1938 to 1941

George, W. G. and C. L. Casler. 1972. Auk: 89(2): 245-262.
Subalular Apterium in Birds

Remsen, J. V., Jr., M. A. Hyde and A. Chapman. 1993. Condor: 95(1): 178-192.
The Diets of Neotropical Trogons, Motmots, Barbets and Toucans