@misc{indiciae281e9f60000b,
  title = {Lead isotope compositions as guides to early gold mineralization: The North Amethyst vein system, Creede district, Colorado},
  author = {Nora K. Foley and Robert A. Ayuso},
  year = {1994},
  doi = {10.2113/gsecongeo.89.8.1842},
  url = {https://pubs.usgs.gov/publication/70017420},
  note = {Source identifier: 70017420}
}