LAIZĀNE, I. Ecological Education of Society. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference, Rezekne, Latvia, v. 1, p. 154–165, 2006. DOI: 10.17770/etr2003vol1.2001. Disponível em: https://journals23.rta.lv/index.php/ETR/article/view/2001.. Acesso em: 17 apr. 2025.