SÖDERHOLM, Svante. Sex ratio among wintering Pochards Aythya ferina at Erstavik, Sörmland. Ornis Svecica, Lund, Sweden, v. 13, n. 1, p. 17–23, 2003. DOI: 10.34080/os.v13.22816. Disponível em: https://journals.lub.lu.se/os/article/view/22816. Acesso em: 19 apr. 2024.