TY  - RPRT
TI  - Aeromagnetic map of Philadelphia and vicinity, Pennsylvania
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1974
DO  - 10.3133/ofr74370
UR  - https://pubs.usgs.gov/publication/ofr74370
ID  - ofr74370
ER  -