OLLIER, Clifford. Problems of geotourism and geodiversity. Quaestiones Geographicae, [S. l.], v. 31, n. 3, p. 57–61, 2012. DOI: 10.2478/v10117-012-0025-5. Disponível em: https://pressto.amu.edu.pl/index.php/qg/article/view/v10117-012-0025-5. Acesso em: 6 may. 2024.