WICKRAMASINGHE, R. Need for an Ecological Index. Envigogika, Praha, Czech Republic, v. 2, n. 3, 2007. DOI: 10.14712/18023061.330. Disponível em: https://www.envigogika.cuni.cz/index.php/Envigogika/article/view/330. Acesso em: 25 kvě. 2022.