TY  - RPRT
TI  - Lithology and aggregate quality attributes for the digital geologic map of Colorado
AU  - Daniel H. Knepper
AU  - Gregory N. Green
AU  - William H. Langer
PY  - 1999
DO  - 10.3133/ofr9929
UR  - https://pubs.usgs.gov/publication/ofr9929
ID  - ofr9929
ER  -