TY  - RPRT
TI  - Aeromagnetic map of the Petersham quadrangle, Worcester County, Massachusetts
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1970
DO  - 10.3133/gp699
UR  - https://pubs.usgs.gov/publication/gp699
ID  - gp699
ER  -