SGEM 2019 : 19th international multidisciplinary scientific geoconference SGEM 2019, 30 June - 6 July, 2019, Albena, Bulgaria. 19, 2. Hydrogeology, Engineering Geology and Geotechnics . Sofia :  STEP92 Technology , 2019 . 1171 s . ISBN 978-619-7408-77-5
http://dx.doi.org/10.5593/sgem2019/1.2 .