@misc{indiciaec27ceefa7f99,
  title = {Joint patterns in sandstone and quartzose siltstone in the Appalachian basin},
  author = {William J. Perry and G. W. Colton and Jean D. MacKenzie},
  year = {1981},
  doi = {10.3133/ofr81838},
  url = {https://pubs.usgs.gov/publication/ofr81838},
  note = {Source identifier: ofr81838}
}