Peck, J. A. Digital conversion of Peck, J.H., 1975, Preliminary bedrock geologic map of the Clinton quadrangle, Worcester County, Mass., U.S. Geological Survey Open File Report 75-658. Digital Conversion (2012).

T. Dale, N. The commercial granites of New England. 448 (United States Geological Survey, 1923). at <https://pubs.er.usgs.gov/publication/b738>