1. Banks, R. (1997). Commanders’ display of terrain information: manipulations of display dimensionality and frame of reference to support battlefield visualization. Unpublished master’s thesis, University of Illinois, Urbana-Champaign.
2. Barsam, H. F., & Simutis, Z. M. (1984). Computer-based graphics for terrain visualization training. Human Factors, 26(6), 659–665.
3. Lect Notes Comput Sci;M. J. Egenhofer,1995
4. Ellis, C. D. (1998). The Effectiveness of Qualitative Spatial Representation in Supporting Spatial Awareness and Spatial Decision Making. Unpublished Ph.D. Dissertation, University of Illinois, Urbana, Illinois.
5. Frank, A. (1992). Qualitative reasoning about distance and directions in geographic space. Journal of Visual Languages and Computing, 3(4), 343–371.