LIMPERT, Roland J; SLADEN, William J L; ALLEN, JR, Hubert A. Winter distribution of Tundra Swans Cygnus columbianus breeding in Alaska and Western Canadian Arctic. Wildfowl, [S. l.], p. 78–83, 2013. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154994. Acesso em: 17 dec. 2025.