1. American Ornithologists' Union, “Check Lists of North American Birds”, fifth ed. (Lord Baltimore Press, Baltimore, Md., 1957).
2. Cooch, F. G., “A Preliminary Study of Blue and Lesser Snow Geese on Southampton Island”, M.S. thesis (unpub.), Cornell University (1953).
3. Blaauw, F. E., Ibis, Ser. 8, 4, 67 (1908).
4. Mayr, E., “Systematics and the Origin of the Species” (1942).
5. Sutton, G. M., Carneg. Mus. Mem., 12 (2), 3 (1932).