BOYD, Hugh; OGILVIE, Malcolm. Losses of Mute Swans in England in the winter of 1962-63. Wildfowl, [S. l.], v. 15, p. 4, 1964. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/155183. Acesso em: 5 apr. 2026.