Söderholm, Svante. “Sex Ratio of the Eurasian Wigeon Anas Penelope During Spring Migration at Angarnsjöängen, Uppland, 1995—2005”. Ornis Svecica 17, no. 3–4 (October 1, 2007): 113–120. Accessed November 22, 2024. https://journals.lub.lu.se/os/article/view/22682.