Nikitin, Oleg, Erik Väli, Sergei Sabanov, and Jyri-Rivaldo Pastarus. “THE SURFACE MINER SUSTAINABLE TECHNOLOGY INTRODUCTION FOR OIL-SHALE MINING IN ESTONIA”.
ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 23, 2007): 55–61. Accessed May 2, 2025.
https://journals.ru.lv/index.php/ETR/article/view/1735.