@misc{indiciae60fbb4df1f0c,
  title = {Geology of Bulgaria: A review},
  author = {Richard M. Foose and Frank T. Manheim},
  year = {1975},
  doi = {10.1306/83d91c81-16c7-11d7-8645000102c1865d},
  url = {https://pubs.usgs.gov/publication/70207490},
  note = {Source identifier: 70207490}
}