@article {5586, title = {National Park Digital Guide: The Complete National Park Collection}, year = {2003}, publisher = {Maptech, Inc.}, type = {Electronic Resource}, address = {Amesbury, MA}, keywords = {Camping, Geology, History, Mapping, Topography} } @article {5730, title = {Appalachian Trail Digital Guide USGS Topographic Maps}, year = {1999}, note = {4 computer laser optical discs.}, publisher = {Maptech, Inc.}, address = {Greenland, NH}, keywords = {Appalachian Trail, Mapping, Trails} }