TY  - RPRT
TI  - Geologic mapping in the United States
AU  - Leona Boardman
PY  - 1949
DO  - 10.1130/0016-7606(1949)60[1125:gmitus]2.0.co;2
UR  - https://pubs.usgs.gov/publication/70215519
ID  - 70215519
ER  -