ALFARO, María del Rosario. The Air a Resource Without Borders, discussed in Agenda 21. Tropical Journal of Environmental Sciences, [S. l.], v. 10, n. 1, p. 39–47, 1993. DOI: 10.15359/rca.10-1.7. Disponível em: https://www.revistas.una.ac.cr/index.php/ambientales/article/view/13034.. Acesso em: 3 jul. 2024.