JÄRVINEN, O.; VÄISÄNEN, R. A. Estimating relative densities of breeding birds by the line transect method. IV. Geographical constancy of the proportion of main belt observations. Ornis Fennica, [S. l.], v. 53, n. 3, p. 87–91, 1976. Disponível em: https://ornisfennica.journal.fi/article/view/132905. Acesso em: 8 may. 2024.