Reinertsen , Randi Eidsmo. “Nocturnal Hypothermia and Its Energetic Significance for Small Birds Living in the Arctic and Subarctic Regions. A Review”. Polar Research 1, no. 3 (January 1, 2010): 269-284. Accessed March 29, 2026. https://polarresearch.net/index.php/polar/article/view/2568.