MATHIASSON, Sven. Eurasian Whooper Swan Cygnus cygnus migration with particular reference to birds wintering in southern Sweden. Wildfowl, [S. l.], p. 201–208, 2013. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154978. Acesso em: 17 dec. 2025.