@misc{indiciae49d97e4b707a,
  title = {Philadelphia Merchants' Exchange conservation strategy; marble characteristics and deterioration},
  author = {E. S. McGee},
  year = {1996},
  doi = {10.3133/ofr96519},
  url = {https://pubs.usgs.gov/publication/ofr96519},
  note = {Source identifier: ofr96519}
}