@misc{indiciaede4ce2e49fbc,
  title = {In situ analysis of coal using a 252CF-Ge(Li) borehole sonde},
  author = {F. E. Senftle and A. B. Tanner and P. W. Philbin and G. R. Boynton and C. W. Schram},
  year = {1977},
  doi = {10.3133/ofr77162},
  url = {https://pubs.usgs.gov/publication/ofr77162},
  note = {Source identifier: ofr77162}
}