SWENNEN, C; DUIVEN, P; WINTERMANS, G J M. Abnormal plumage in possibly senile female Eiders Somateria mollissima. Wildfowl, [S. l.], p. 127–130, 1989. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154006. Acesso em: 17 dec. 2025.