1. Frank A. (1984). Classnotes from computer cartography I . Surveying Engineering Program University of Maine Orono Me.
2. GPS resource package . (1987). GPS Committee New Mexico Geographic Information Council Albuquerque N.M.
3. Lambert S. (1987). “Monitoring vertical crustal deformation in eastern Maine using GPS and derived orthometric heights ” thesis presented to the University of Maine at Orono Me. in partial fulfillment of the requirements for the degree of Master of Science.
4. Leick A. ed. (1980). “Land information at the local level.” Proc. University of Maine.
5. Leick A. (1987). GIS point referencing by satellite and gravity . Surveying Engineering Program University of Maine Orono Me.