Kampe-Persson, Hakon, Dmitrijs Boiko, and Julius Morkūnas. “Distribution and Numbers of Moulting Non-Breeding Whooper Swans Cygnus Cygnus in the Baltic States and South Sweden”. Ornis Svecica 22, no. 3–4 (October 1, 2012): 127–138. Accessed April 20, 2024. https://journals.lub.lu.se/os/article/view/22588.