CRANSWICK, P A; BOWLER, J M; DELANY, S N; EINARSSON, O; GARDARSSON, A; MCELWAINE, J G; MERNE, O J; REES, E C; WELLS, J H. Numbers of Whooper Swans Cygnus cygnus in Iceland, Ireland and Britain in January 1995: results of the international Whooper Swan census. Wildfowl, [S. l.], p. 17–30, 1996. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154646. Acesso em: 17 dec. 2025.