OLSON, David. Rocky Mountain Population of Trumpeter Swans Cygnus buccinator (U.S. Breeding Segment): results of the autumn 2022 survey and long-term trends. Wildfowl, [S. l.], p. 76–88, 2024. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/161406. Acesso em: 16 dec. 2025.