Bengtsson, Kenneth, and Kjeld T Pedersen. “The Occurrence of Eastern Common Gulls Larus Canus Heinei in the Region of Öresund”. Ornis Svecica 8, no. 4 (October 1, 1998): 145–156. Accessed April 28, 2024. https://journals.lub.lu.se/os/article/view/22939.