Zapušek, Alenka, Gorazd Berčič, Simon Zavšek, Ludvik Golob, Igor Veber, and Damjan Konovšek. “UNDERGROUND COAL GASIFICATION (UCG) – THE VELENJE COAL MINE EXPERIENCE”. Journal of Energy Technology 4, no. 1 (May 6, 2024): 61–76. Accessed February 26, 2026. https://old.journals.um.si/index.php/jet/article/view/4310.