↑ abKuhl, Heinrich (1820). "Castor Canadensis". Beiträge zur Zoologie und vergleichenden Anatomie. Frankfurt: Verlag der Hermannschen Buchhandlung. pp. 64–65.
↑ abBailey, Vernon; Doutt, J. Kenneth. 1942. Two New Beavers from Labrador and New Brunswick. Journal of Mammalogy. 23 (1): 86–88. doi:10.2307/1374859. JSTOR 1374859
↑Allen, Glover M. 1942. Newfoundland Beaver. Extinct and Vanishing Mammals of the Western Hemisphere, with the Marine Species of All the Oceans. American Committee for International Wild Life Protection. str. 62–63
↑Warren, Edward R.; Hall, E. Raymond. 1939. A New Subspecies of Beaver from Colorado. Journal of Mammalogy. 20 (3): 358–362. doi:10.2307/1374265. JSTOR 1374265
↑ abcDurrant, Stephen D.; Crane, Harold. 1948. Three New Beavers from Utah. University of Kansas Publications, Museum of Natural History. 1 (20): 407–417
↑Bailey, V. 1919. A New Subspecies of Beaver from North Dakota. Journal of Mammalogy. 1 (1): 31–32. doi:10.1093/jmammal/1.1.31. JSTOR 1373717
↑Heller, Edmund. 1909. The Mammals. University of California Publications in Zoology. 5 (2, Birds and Mammals of the 1907 Alexander Expedition to Southeastern Alaska): 250–255
↑Goldman, E. A. 1932. A New Beaver from Arizona. Journal of Mammalogy. 13 (3): 266–267. doi:10.2307/1374004. JSTOR 1374004
↑Benson, Seth B. 1933. A New Race of Beaver from British Columbia. Journal of Mammalogy. 14 (4): 320–325. doi:10.2307/1373950. JSTOR 1373950