@proceedings{sgem2012v4,
  title = {12th International Multidisciplinary Scientific GeoConference SGEM 2012, Conference Proceedings, Vol. 12, Volume 4},
  author = {International authors},
  year = {2012},
  publisher = {STEF92 Technology},
  isbn = {},
  doi = {10.5593/sgem2012/v4}
}