@misc{indiciae2093840cd25d,
  title = {Program to prepare standard figures for grade-tonnage models on a Macintosh},
  author = {Donald A. Singer and James D. Bliss},
  year = {1990},
  doi = {10.1016/b978-0-08-040261-1.50026-x},
  url = {https://pubs.usgs.gov/publication/70197266},
  note = {Source identifier: 70197266}
}