Koskimies, J. “Observations on the Development of Mobility in Young Common Gulls, Larus Canus L., and Lesser Blackbacked Gulls, L. Fuscus L”. Ornis Fennica 29, no. 3 (September 30, 1952): 83–87. Accessed September 17, 2024. https://ornisfennica.journal.fi/article/view/132551.