@inproceedings{sgem2021s05099,
  title = {SEISMICITY IN BULGARIA AND SURROUNDINGS IN THE FIRST 20 YEARS OF THE TWENTY-FIRST CENTURY},
  author = {Maria Popova and Dragomir Dragomirov and Emil Oynakov and Valentin Buchakchiev and Yordan Milkov},
  booktitle = {SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 21st SGEM International Multidisciplinary Scientific GeoConference Proceedings 2021, Science and Technologies in Geology, Exploration And Mining},
  year = {2021},
  pages = {551-558},
  publisher = {STEF92 Technology},
  doi = {10.5593/sgem2021/1.1/s05.099}
}