2 literature references:

Author: Banks, R. C., R. W. McDiarmid, and A. L. Gardner
Year: 1987
Title: Checklist of Vertebrates of the United States, the U.S. Territories, and Canada
Source: Resource Publication, no. 166
Author: Gill, Frank, and Minturn Wright
Year: 2006
Source: Birds of the World: Recommended English Names