Tretjakova, Rasma, and Andris Karpovičs. “MINERAL COMPOSITION OF SOME LATGALE LAKE SEDIMENTS”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 20, 2019): 304–306. Accessed January 2, 2025. https://journals23.rta.lv/index.php/ETR/article/view/4146.