TY  - RPRT
TI  - Porphyry gold; a supplement to U.S. Geological Survey bulletin 1693
AU  - J. J. Rytuba
AU  - D. P. Cox
PY  - 1991
DO  - 10.3133/ofr91116
UR  - https://pubs.usgs.gov/publication/ofr91116
ID  - ofr91116
ER  -