Digital Versions of Older NEIGC Guidebooks (1920-1989). at <http://www.library.unh.edu/digital/category/science-technology>

The Dynamic Digital Map of New England by Chris Condit (U-Mass, Amherst). at <http://ddm.geo.umass.edu/ddm-ne/index.html>

NEIGC Fieldtrip guidebooks for various parts of New England. at <http://w3.salemstate.edu/ lhanson/NEIGC/Guidebooks.html>

Roadside Geology of Massachusetts. at <http://mountain-press.com/item_detail.php?item_key=606>