Tretjakova, Rasma, Gotfrīds Noviks, and Gundars Mežinskis. 2019. “INVESTIGATION OF STRUCTURE AND COMPOSITION OF CLAY IN LAKES OF LATGALE FOR PRACTICAL USE”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June): 298-303. https://doi.org/10.17770/etr2019vol1.4069.