Bensch, Staffan, Hans Källander, and Robert Lager. “Mass and Wing Length of Young Black-Headed Gulls Larus Ridibundus As Predictors of Age and Survival”. Ornis Svecica 6, no. 1–2 (April 1, 1996): 57–66. Accessed June 30, 2024. https://journals.lub.lu.se/os/article/view/22995.