NILSSON, L. Distribution, population size and long-term changes in population size of wintering waterfowl in Sweden. Ornis Svecica, Lund, Sweden, v. 1, n. 1, p. 11–28, 1991. DOI: 10.34080/os.v1.23092. Disponível em: https://journals.lub.lu.se/os/article/view/23092. Acesso em: 5 dec. 2022.