TY  - RPRT
TI  - Sedimentary phosphate resources classification system of the U.S. Bureau of Mines and the U.S. Geological Survey
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1982
DO  - 10.3133/cir882
UR  - https://pubs.usgs.gov/publication/cir882
ID  - cir882
ER  -