^University of Michigan. Ursus Americanus. [2013-01-16]. (原始内容存档于2012-11-04).
^ 8.08.18.28.38.48.5Anamnese en lichamelijk onderzoek bij gezelschapsdieren, A.Rijnberk, F.J.van Sluis, 2nd print, Bohn Stafleu van Loghum, 2005, (Current Dutch veterinary examination study book for small domestic mammals)
^Botaya, Emilio Magallón. Husbandry and Management Practices in Farrowing Units: Farrowing. I. Grupo Asís Biomedia, 2014.
^The Laboratory Rat , 2nd Edition, Eds. Mark A. Sucklow, Steven H. Weisbroth, and Craig L. Franklin. Page 151.