Hall, Colette, Jacqueline Glanville, Helen Boland, Ólafur Einarsson, Graham McElwaine, Chas A Holt, Christopher J Spray, and Eileen C Rees. “Population Size and Breeding Success of Icelandic Whooper Swans Cygnus Cygnus: Results of the 2010 International Census”. Wildfowl (January 1, 2012): 73–96. Accessed December 16, 2025. https://tidsskrift.dk/Wildfowl/article/view/153572.