Mathiasson, Sven. “A Moulting Population of Non-Breeding Mute Swans With Special Reference to Flight-Feather Moult, Feeding Ecology and Habitat Selection”. Wildfowl (January 1, 1973): 43–53. Accessed February 13, 2026. https://tidsskrift.dk/Wildfowl/article/view/154883.