Lif, Mattias, Måns Hjernquist, Olof Olsson, and Henrik Österblom. “Long-Term Population Trends in the Lesser Black-Backed Gull Larus F. Fuscus at Stora Karlsö and Lilla Karlsö, and Initial Results on Breeding Success”. Ornis Svecica 15, no. 2 (April 1, 2005): 105–112. Accessed July 6, 2022. https://journals.lub.lu.se/os/article/view/22745.