SÖDERHOLM, Svan. Does the Pochard Aythya ferina vary periodically?—an analysis of census data from Angarnsjöängen, Sweden 1978—2003 and Lake Engure, Latvia 1972—1992. Ornis Svecica, Lund, Sweden, v. 16, n. 3, p. 85–94, 2006. DOI: 10.34080/os.v16.22712. Disponível em: https://journals.lub.lu.se/os/article/view/22712. Acesso em: 25 apr. 2024.