Norment, C. J.; Hendricks, P.; Santonocito, R. (1998). "Golden-crowned Sparrow (Zonotrichia atricapilla)". In Poole, A. (ed.). The Birds of North America Online. Ithaca: Cornell Lab of Ornithology. Retrieved 6 June 2012.
Judd, Sylvester Dwight (1898). "Birds as Weed Destroyers". Yearbook of the Department of Agriculture. Washington, DC, USA: Department of Agriculture. p. 226. Archived from the original on 2013-04-08. Retrieved 2012-07-20.
web.archive.org
Judd, Sylvester Dwight (1898). "Birds as Weed Destroyers". Yearbook of the Department of Agriculture. Washington, DC, USA: Department of Agriculture. p. 226. Archived from the original on 2013-04-08. Retrieved 2012-07-20.