DE LEEUW, Joep J; BEEKMAN, Jan H. Growth and biometry of Mute Swan Cygnus olor cygnets in Groningen, the Netherlands. Wildfowl, [S. l.], p. 288–295, 2013. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154958. Acesso em: 17 dec. 2025.