@inproceedings{sgem2008paper,
  title = {MINE VENTILATION SHAFTS – STRUCTURAL INTERVENTION FOR SOUNDPROOFING},
  author = {N. Zhechev},
  booktitle = {8th International Scientific Conference - SGEM2008},
  year = {2008},
  pages = {133-138},
  publisher = {SGEM Scientific GeoConference},
  doi = {}
}