SGEM SGEM 2019. 19th International Multidisciplinary Scientific GeoConference. Volume 19. Science and Technologies in Geology, Exploration and Mining : conference proceedings. Albena, Bulgaria, 30 June - 6 July 2019 Issue 1.2 Hydrogeology, Engineering Geology and Geotechnics, Oil and Gas Exploration. -- 1. vyd. -- Sofia : STEF 92 Technology, 2019. -- 1171 s. -- ISBN : 978-619-7408-77-5. -- ISSN : 1314-2704. -- 10.5593/sgem2019/1.2.