Pužule, Valentīna, and Gotfrids Noviks. “KUPRAVA CLAY DEPOSIT RESEARCH COMPARISON”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 20, 2019): 236–240. Accessed December 22, 2024. https://journals23.rta.lv/index.php/ETR/article/view/4164.