Rainer Hutterer. Zoologisches Forschunginstitut und Museum Alexander Koenig, Adenauerallee 160, 53113 Bonn, Germany
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.
Wilson, Don E., and F. Russell Cole 2000-01-01. Common Names of Mammals of the World. Smithsonian Institution Press. Washington, DC, USA. xiv + 204. 1-56098-383-3. With contributions by Bernadette N. Graham, Adam P. Potter, and Mariana M. Upmeyer.
Wilson & Reeder, eds. (2005): Status: IUCN - Lower Risk (lc)
Wilson & Reeder, eds. (2005): Comments: Husson and Heurn (1959) recognized and named twelve color morphs from the Netherlands that are not listed here. Does not include altaica, caucasica, romana, and stankovici; see comments under these species. Only europaea and cinerea were regarded as subspecies by Niethammer (in Niethammer and Krapp, 1990). Do?ramaci (1989) considered velessiensis as the valid subspecies for Turkish Thrace. A biological review of the species was provided by Witte (1997). Karyotype has 2n = 34, FN = 68 (Krato...