Meissner, Włodzimierz, and Katarzyna Ciopcińska. “Behaviour of Mute Swans Cygnus Olor Wintering at a Municipal Beach in Gdynia, Poland”. Ornis Svecica 17, no. 3–4 (October 1, 2007): 148–153. Accessed April 19, 2024. https://journals.lub.lu.se/os/article/view/22685.