TY  - RPRT
TI  - Historical trends in U.S. mineral statistics for selected non-ferrous metals
AU  - David Z. Piper
AU  - Warren J. Nokleberg
PY  - 2002
DO  - 10.3133/ofr0229
UR  - https://pubs.usgs.gov/publication/ofr0229
ID  - ofr0229
ER  -