SEARS, Jane. Feeding activity and body condition of Mute Swans Cygnus olor in rural and urban areas of a lowland river system. Wildfowl, [S. l.], p. 88–98, 1989. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154017. Acesso em: 17 dec. 2025.