CRANSWICK, P A; KIRBY, J S; SALMON, D G; ATKINSON-WILLES, G L; POLLITT, M S; OWEN, M. A history of wildfowl counts by The Wildfowl & Wetlands Trust. Wildfowl, [S. l.], p. 216–229, 1996. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154637. Acesso em: 17 dec. 2025.