@proceedings{sgem202151,
  title = {21st International Multidisciplinary Scientific GeoConference SGEM 2021, Ecology, Environmental Economics, Education, and Legislation, Vol. 21, Issue 5.1},
  author = {International authors},
  year = {2021},
  publisher = {STEF92 Technology},
  isbn = {},
  doi = {10.5593/sgem2021/5.1}
}