@inproceedings{sgem2018s02074,
  title = {PROBLEMS OF ECOLOGY AND SECURITY IN THE CONTACT AREA BETWEEN OLD AND NEW TUNNELS},
  author = {Nikolay Zhechev},
  booktitle = {SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 18th International Multidisciplinary Scientific GeoConference SGEM2018, Science and Technologies in Geology, Exploration and Minining},
  year = {2018},
  pages = {585-592},
  publisher = {STEF92 Technology},
  doi = {10.5593/sgem2018/1.2/s02.074}
}