Alfred L. Gardner. Curator of North American mammals and Chief of Mammal Section, National Biological Service, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
Peter Grubb. 35 Downhills Park Road, London N17 6PE, England
Banks, R. C., R. W. McDiarmid, and A. L. Gardner 1987-01-01. Resource Publication, no. 166. United States Department of the Interior Fish and Wildlife Service. Washington, D.C., USA. 79. . .
Wilson, Don E., and Sue Ruff, eds. 1999-01-01. The Smithsonian Book of North American Mammals. Smithsonian Institution Press. Washington, DC, USA. xxv + 750. 1-56098-845-2. .
Wilson, Don E., and DeeAnn M. Reeder, eds. 2005-10-01. Mammal Species of the World: A Taxonomic and Geographic Reference, 3rd ed., vols. 1 & 2. Johns Hopkins University Press. Baltimore, Maryland, USA. 2142. 0-8018-8221-4. .
Wilson, Don E., and DeeAnn M. Reeder, eds. 1992-01-01. Mammal Species of the World: A Taxonomic and Geographic Reference, 2nd ed., 3rd printing. Smithsonian Institution Press. Washington, DC, USA. xviii + 1207. 1-56098-217-9. Corrections were made to text at 3rd printing.
Banks, R. C., R. W. McDiarmid, A. L. Gardner, and W. C. Starnes 2003-12-31. Checklist of Vertebrates of the United States, the U.S. Territories, and Canada. . . . . As-yet (2003) unpublished manuscript from 1998.
Wilson & Reeder, eds. (2005): Comments: Placed in Capra by Van Gelder (1977b); see comments under Capra. There is no consensus concerning the number of species to be recognized in this genus; some would recognize only one (ammon; see Haltenorth, 1963:126-128); others two (ammon, canadensis; see Corbet, 1978c:218); while others recognize up to seven, as do the most recent reviews (Korobitsyna et al., 1974; Nadler et al., 1973). Five species are listed here. Species-groups are nominate Ovis or aries group (includes also ammon) and ...