Kumar, Sikandar, Rabindra Kumar Sinha, and Mohammad Jawed. “A Global Overview of the Schemes of Extraction of Pillars in Major Coal Producing Countries”. Journal of Mines, Metals and Fuels 70, no. 10 (April 4, 2023): 528–536. Accessed May 20, 2024. http://www.informaticsjournals.com/index.php/jmmf/article/view/32292.