KAMPE-PERSSON, H.; BOIKO, D. Occurrence of swan hybrids around the Baltic Sea—an outcome of range expansions?. Ornis Svecica, Lund, Sweden, v. 21, n. 1, p. 45–54, 2011. DOI: 10.34080/os.v21.22609. Disponível em: https://journals.lub.lu.se/os/article/view/22609. Acesso em: 5 dec. 2022.