GEIST, Valerius. Defining subspecies, invalid taxonomic tools, and the fate of the woodland caribou. Rangifer, Tromsø, Norway, v. 27, n. 4, p. 25–28, 2007. DOI: 10.7557/2.27.4.315. Disponível em: https://septentrio.uit.no/index.php/rangifer/article/view/315. Acesso em: 2 may. 2026.