Pulliainen, E. “The Invasions of the Kittiwake (Rissa Tridactyla) into Finland in February and March 1959 and 1962”. Ornis Fennica 39, no. 3 (September 30, 1962): 81–96. Accessed April 20, 2025. https://ornisfennica.journal.fi/article/view/132673.