@misc{indiciae48170951bc6f,
  title = {Coal resources of southwestern Washington},
  author = {Helen Marie Beikman and Howard D. Gower},
  year = {1959},
  doi = {10.3133/ofr596},
  url = {https://pubs.usgs.gov/publication/ofr596},
  note = {Source identifier: ofr596}
}