1. Chen Lichao, Zhang Yongmei, Liu Yushu and Zhang Jianhua, 3D Spatial Data Models of GIS Based on Grid. Computer Engineering, Vol. 30 No. 8 (2004).
2. Shinji Araya, Jin Hyunsuk and Ryo Araya. An Effective Terrain Model for Web-Based 3D Geographic Information Systems. Electronics and Communications in Japan Part 2, Vol. 85 No. 9 (2002).
3. Elizabeth Burson. Modeling Unordered Point Data for 3D GIS Mapping - approaches for improved usability and accuracy. charlotte .utdallas edu/mgis/ prj_mstrs/2003/03_burson/ EBurson_Masters.pdf, (2003).
4. Zhang Jing and Zhang Zhengrong. 3D Visualization about Urban GIS. www.china-simulation.com/esite/preview/0312.htm , Vol. 15 No. 12 (2003).
5. Kolbe T. H. and Groger G. Towards Unified 3D City Models. http://www.iuw.univechta,de/personal/geoinf/jochen/papers/28.pdf ,de/personal/geoinf/jochen/papers/28.pdf, (2003).