SIIVONEN, L. Densities of the willow warbler, Phylloscopus trochilus (L), doubled in a year. Ornis Fennica, [S. l.], v. 27, n. 3, p. 68–72, 1950. Disponível em: https://ornisfennica.journal.fi/article/view/132529. Acesso em: 18 touko. 2024.