J.P., K., Roden-Tice, M. K. & Wintsch, R. P. Latest Paleozoic through Mesozoic faults in north-central Massachusetts and their correlations with New Hampshire. Geological Society of America - Northeastern section (Geological Society of America, 2016). doi:10.1130/abs/2016NE-272576

J.P., K. Bedrock geologic map of the Ayer 7.5? quadrangle, Worcester and Middlesex Counties, Massachusetts. Open File Report

Kopera, J. P. Bedrock geologic map of the Ayer 7.5? quadrangle, Worcester and Middlesex Counties, Massachusetts (2015). Open File Report

Kopera, J. P. Preliminary bedrock geologic map of the Ayer quadrangle, Massachusetts. Open-File Report (2006). at <http://www.geo.umass.edu/stategeologist/>