Nilsson, Leif. “Survey of Wintering Whooper Swans Cygnus Cygnus in Sweden in January 2015, and Habitat Shift in 1995–2015”. Ornis Svecica 26, no. 1 (January 1, 2016): 55–60. Accessed November 22, 2024. https://journals.lub.lu.se/os/article/view/22532.