TY  - RPRT
TI  - Bedrock geologic map of the Pepperell, Shirley, Townsend quadrangles, and part of the Ayer Quadrangle, Massachusetts and New Hampshire
AU  - G.R. Robinson
PY  - 1978
DO  - 10.3133/mf957
UR  - https://pubs.usgs.gov/publication/mf957
ID  - mf957
ER  -