Gerhart, K. L., R. G. White, R. D. Cameron, D. E. Russell, and D. van de Wetering. “Pregnancy Rate As an Indicator of Nutritional Status in Rangifer. Implications of Lactational Infertility”. Rangifer 17, no. 1 (April 1, 1997): 21-24. Accessed March 4, 2021. https://septentrio.uit.no/index.php/rangifer/article/view/381.