Baimolda D, Lennik S, and Didarbek P. “STUDY OF CHEMICAL ELEMENTS IN THE COMPOSITION OF THE SHUBARKOL COAL BY X-RAY FLUORESCENCE METHOD”. Foundations and Trends in Modern Learning, no. 11 (December 1, 2025). Accessed October 23, 2026. https://ojs.scipub.de/index.php/FTML/article/view/7217.