Bengtsson, Kenneth, and Lennarth Blomquist. “Origin, Migration, and Site Fidelity of Black-Headed Gulls Larus Ridibundus Ringed at Malmö”. Ornis Svecica 11, no. 1–2 (April 1, 2001): 59–77. Accessed May 3, 2024. https://journals.lub.lu.se/os/article/view/22860.