DIRECT AND SUPPLEMENTARY SHADOWS IN THE TASK OF THE EFFICIENT DESCRIPTION OF CLASSES. ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference, [S. l.], v. 1, p. 32–32, 1999. DOI: 10.17770/etr1999vol1.1911. Disponível em: https://archive-journals.rtu.lv/etr/article/view/3419.. Acesso em: 11 mar. 2026.