@misc{indiciae5c710d31b969,
  title = {Tapping the Earth's natural heat},
  author = {Wendell A. Duffield and J.H. Sass and M.L. Sorey},
  year = {1994},
  doi = {10.3133/cir1125},
  url = {https://pubs.usgs.gov/publication/cir1125},
  note = {Source identifier: cir1125}
}