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
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 As-yet (2003) unpublished manuscript from 1998.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: Reviewed by Coutourier (1962). Includes Orthaegoceros; see Heptner et al. (1961:593). Some authors have included Ammotragus and Ovis; see Ansell (1972:70) and Van Gelder (1977b). However, most authors have not followed this arrangement; see Gray and Simpson (1980), Gromov and Baranova (1981), Hall (1981), and Corbet and Hill (1991). There is no consensus concerning the number of species to be recognized in this genus; some would recognize only two (hircus and falconeri; see Haltenorth, 1963...