ELTRINGHAM, S K; ATKINSON-WILLES, G L. Recent population changes in British ducks, 1948 to 1960. Wildfowl, [S. l.], v. 12, p. 40–57, 1961. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/155754. Acesso em: 19 apr. 2026.