@inproceedings{sgem2017s02005,
  title = {ABOUT A HALF-WAVE LENGTH OF THE BOTTOM-HOLE CORE DRILL COMPOSED OF STRUCTURAL ELEMENTS OF DIFFERENT STIFFNESS},
  author = {Boranbay Ratov},
  booktitle = {SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 17th International Multidisciplinary Scientific GeoConference SGEM2017, Science and Technologies in Geology, Exploration and Mining},
  year = {2017},
  pages = {33-43},
  publisher = {STEF92 Technology},
  doi = {10.5593/sgem2017/12/s02.005}
}