1. Frank, A.U., Mark, D.M.: Language issues for GIS. In: Macguire, D., Goodchild, M. F. and Rhind, D(eds): Geographical Information Systems: Principles and Applications, pp. 147-163. Wiley, New York (1991)
2. Mark, D.M., Frank, A.U.: User interfaces for Geographic Information Systems: report on the specialist meeting. National Center for Geographic Information and Analysis (1992)
3. Mark, D.M., Svorou, S., Zubin, D.: Spatial terms and spatial concepts: Geographic, cognitive, and linguistic perspectives. In: Proceedingsof International Geographic Information Systems (IGIS) Symposium: The Research Adgenda, Arlington, VA, pp. 101–112 (1987)
4. Shapiro, S.C., Chalupski, H., Chou, H.C.: Linking ARC/INFO with SNACTor. National Center for geographic Information and Analysis, Santa Barbara (1991)
5. Neal, J.G., Shapiro, S.C.: Intelligent Multi-Media Interface Technology. In: Sullivan, J.W., Tyler, S.W. (eds.) Architectures for Intelligent Interfaces: Elements and Prototypes, pp. 11–44. Addison-Wesley, Massachusetts (1991)