TY  - RPRT
TI  - Geologic reconnaissance map of the Rules Hill and Ludwig Mountain quadrangles, La Plata County, Colorado
AU  - W. J. Hail
AU  - Harley Barnes
AU  - A.D. Zapp
PY  - 1971
DO  - 10.3133/ofr71143
UR  - https://pubs.usgs.gov/publication/ofr71143
ID  - ofr71143
ER  -