@misc{indiciae6c910fa90697,
  title = {Estimates of undiscovered recoverable resources of total gas by province; statistical background data for U.S. Geological Survey Circular 860},
  author = {K. L. Varnes and G.L. Dolton and Ronald R. Charpentier},
  year = {1982},
  doi = {10.3133/ofr82666d},
  url = {https://pubs.usgs.gov/publication/ofr82666D},
  note = {Source identifier: ofr82666D}
}