Eric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545; Supplemental material 2 table S1b. [1]
"Large herbivores". European bison (Bison bonasus). WWF Global. 13. november 2005. Arkiveret fra originalen(Internet Archive) 13. august 2006. Hentet 22. januar 2013.
"Large herbivores". European bison (Bison bonasus). WWF Global. 13. november 2005. Arkiveret fra originalen(Internet Archive) 13. august 2006. Hentet 22. januar 2013.