@inproceedings{sgem202042, title = {20th International Multidisciplinary Scientific GeoConference SGEM 2020, Energy and Clean Technologies, Vol. 20, Issue 4.2}, author = {International authors}, booktitle = {International Multidisciplinary Scientific GeoConference SGEM 2020}, year = {2020}, pages = {}, publisher = {STEF92 Technology}, doi = {10.5593/sgem2020v/4.2} }