OLSEN, Dave; LONG, Bill; MITCHELL, Carl D. Geographic variation in Trumpeter Swan Cygnus buccinator clutch size and egg weights. Wildfowl, [S. l.], p. 133–142, 2015. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/153665. Acesso em: 16 dec. 2025.