Moen, R., M. A. Olsen, Ø. E. Haga, W. Sørmo, T. H. Aagnes Utsi, and S. D. Mathiesen. “Digestion of timothy silage and hay in reindeer”. Rangifer, vol. 18, no. 1, Feb. 1998, pp. 35-45, doi:10.7557/2.18.1.1444.