DE YONG, R. P.; BACON, P J. Variation in cohesion of a brood of Mute Swans. Wildfowl, [S. l.], v. 30, p. 86–89, 1979. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154144. Acesso em: 15 apr. 2026.