Unander Sigmund, Mortensen Atle, and Elvebakk Arve. “Seasonal Changes in Crop Content of the Svalbard Ptarmigan Lagopus Mutus Hyperboreus”. Polar Research 3, no. 2 (January 12, 1985): 239-245. Accessed May 4, 2024. https://polarresearch.net/index.php/polar/article/view/2528.