TY  - RPRT
TI  - Map showing mined areas of the Boulder-Weld coal field, Colorado
AU  - Roger B. Colton
AU  - R.L. Lowrie
PY  - 1973
DO  - 10.3133/mf513
UR  - https://pubs.usgs.gov/publication/mf513
ID  - mf513
ER  -