Seismic Profile data (Knudsen) published in:
Pendleton, E.A., Andrews, B.D., Danforth, W.W., and Foster, D.S. 2013, High-resolution geophysical data from sand shoals of Vineyard Sound and the seafloor surrounding the eastern Elizabeth Islands, Massachusetts: U.S. Geological Survey Open-File Report 2013-1020, available at http://pubs.usgs.gov/of/2013/1020/
