TY  - RPRT
TI  - Aeromagnetic map of the Pepperell quadrangle, Middlesex County, Massachusetts, and Hillsborough County, New Hampshire
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1971
DO  - 10.3133/gp732
UR  - https://pubs.usgs.gov/publication/gp732
ID  - gp732
ER  -