@misc{indiciae92a81a1556ff,
  title = {Statistical guides to estimating the number of undiscovered mineral deposits: an example with porphyry copper deposits},
  author = {Donald A. Singer and W. D. Menzie},
  year = {2005},
  url = {https://pubs.usgs.gov/publication/70197275},
  note = {Source identifier: 70197275}
}