Fransson, Thord, and Bengt-Olov Stolt. “The Wintering of Blackcaps Sylvia Atricapilla (L.) in Sweden”. Ornis Svecica 4, no. 2–3 (July 1, 1994): 105–123. Accessed April 30, 2024. https://journals.lub.lu.se/os/article/view/23024.