BURTON, P J K. Brent Geese in Essex - The proportion of first-winter birds in flocks of Brent Geese in Essex. Wildfowl, [S. l.], v. 9, p. 5, 1957. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/155503. Acesso em: 19 apr. 2026.