@misc{indiciaeaea2e6d4b592,
  title = {Coalfields of the Republic of Korea, Part 1: Chapters A and B},
  author = {David A. Andrews and Cheong Chang Hi},
  year = {1956},
  doi = {10.3133/b1041ab},
  url = {https://pubs.usgs.gov/publication/b1041AB},
  note = {Source identifier: b1041AB}
}