HISSA, R. Censuses of the nesting birds of the island Lappören in Björkö, W. Finland. Ornis Fennica, [S. l.], v. 41, n. 3–4, p. 69–81, 1964. Disponível em: https://ornisfennica.journal.fi/article/view/132697. Acesso em: 15 may. 2024.