TY  - RPRT
TI  - Guide to selected large-scale geologic maps of southwestern Pennsylvania (west of 78 degrees 45' meridian and south 41 degrees 15' parallel)
AU  - R. P. Briggs
PY  - 1973
DO  - 10.3133/ofr7332
UR  - https://pubs.usgs.gov/publication/ofr7332
ID  - ofr7332
ER  -