@misc{indiciae0137ca641781,
  title = {Schmidt hammer test method for field determination of physical properties of zeolitized tuff},
  author = {John R. Ege and Danny R. Miller and Walter Danilchik},
  year = {1970},
  doi = {10.3133/ofr70117},
  url = {https://pubs.usgs.gov/publication/ofr70117},
  note = {Source identifier: ofr70117}
}