Työppönen, Jouko, Hans Berg, and Maija Valtonen. “Effects of Dietary Supplement of Methionine and Lysine on Blood Parameters and Fur Quality in Blue Fox During Low-Protein Feeding”. Agricultural and Food Science 59, no. 5 (December 1, 1987): 355–360. Accessed May 26, 2024. https://journal.fi/afs/article/view/72268.