@inproceedings{sgem2021s0954,
  title = {SYSTEMS APPROACH TO THE STATE LEVELLING NETWORK OF THE REPUBLIC OF BULGARIA},
  author = {Ivan Kunchev},
  booktitle = {SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 21st SGEM International Multidisciplinary Scientific GeoConference Proceedings 2021, Informatics, Geoinformatics and Remote Sensing},
  year = {2021},
  pages = {213-220},
  publisher = {STEF92 Technology},
  doi = {10.5593/sgem2021/2.1/s09.54}
}