@misc{indiciae5e248e7b9843,
  title = {Determination of the angle of internal means of dynamic drilling},
  author = {A. Couard and S. H. Britt},
  year = {1951},
  doi = {10.3133/ofr5155c},
  url = {https://pubs.usgs.gov/publication/ofr5155C},
  note = {Source identifier: ofr5155C}
}