Sedlak, Vladimir. “MATHEMATICAL DETERMINATION OF SUBSIDENCE BREAK-POINTS IN ABANDONED OLD UNDERMINED REGIONS IN GIS SPACE FOR PURPOSES OF PEOPLE AND PROPERTIES PROTECTION”. European Scientific Journal, ESJ 9, no. 18 (June 30, 2013). Accessed May 13, 2025. https://eujournal.org/index.php/esj/article/view/1176.