Mabee, S. B. Origin of the rocks at Bishop and Clerks shoal and Collier Ledge, Nantucket Sound, Massachusetts: Field report. 36 (Office of the Massachusetts State Geologist, 2004). at <http://www.geo.umass.edu/stategeologist/Products/reports/BCFieldReport.pdf>

Mabee, S. B. Origin of the Rocks at Bishop and Clerks Shoal and Collier Ledge, Nantucket Sound, Massachusetts ? Field Report. 34 (Massachusetts Geological Survey, 2005).