@misc{indiciae76ae1d983ba6,
  title = {Fifth special report of the Hawaiian Volcano Observatory of the Hawaiian Volcano Research Association and the U.S. Geological Survey: Abrasion hardness},
  author = {T. A. Jaggar},
  year = {1950},
  url = {https://pubs.usgs.gov/publication/70232756},
  note = {Source identifier: 70232756}
}