TY  - RPRT
TI  - Summary of United States mineral resources
AU  - Donald Albert Brobst
AU  - Walden P. Pratt
AU  - V.E. McKelvey
PY  - 1973
DO  - 10.3133/cir682
UR  - https://pubs.usgs.gov/publication/cir682
ID  - cir682
ER  -