@inproceedings{sgem2013bd4, title = {13th International Multidisciplinary Scientific GeoConference SGEM 2013, Energy and Clean Technologies, Vol. 13, Book 4}, author = {International authors}, booktitle = {International Multidisciplinary Scientific GeoConference SGEM 2013}, year = {2013}, pages = {}, publisher = {STEF92 Technology}, doi = {10.5593/sgem2013/bd4} }