ATKINSON-WILLES, G L; YARKER, Barbara. Wildfowl censuses and counts in Britain, 1969-70. Wildfowl, [S. l.], v. 21, n. 21, p. 148–149, 1970. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154917. Acesso em: 19 dec. 2025.