HÄSTBACKA, H.; ULFVENS, J. The Mute Swan Cygnus olor in Ostrobothnia in 1970–1986. Ornis Fennica, [S. l.], v. 64, n. 1, p. 27–30, 1987. Disponível em: https://ornisfennica.journal.fi/article/view/133232. Acesso em: 25 nov. 2024.