TŪRISMS, VIDE, APKĀRTĒJĀ SABIEDRĪBA. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference, [S. l.], v. 1, p. 177–179, 1999. DOI: 10.17770/etr1999vol1.1878. Disponível em: https://archive-journals.rtu.lv/etr/article/view/3452.. Acesso em: 11 mar. 2026.