1. Ai T., 2007, The drainage network extraction from contour lines for contour line generalization, ISPRS Journal of Photogrammetry & Remote Sensing 62: 93–103
2. Ai T., Guo RZ, Liu YL. 2000, A Binary Tree Representation of Bend Hierarchical Structure Based on Gestalt Principles. Proceedings of the 9th International Symposium on Spatial Data Handling. Beijing, China, 2000.
3. Band L.E., 1986, Topographic Partition of Watersheds with Digital Elevation Models, Water Resource Research, 22(1):15–24.
4. Boyell R.L. and Ruston H., 1963, Hybrid techniques for real-time radar simulation. In the Proceedings of the 1963 Fall Joint Computer Conference, pages 445–458.
5. Cheung, C. K., Shi, W. (2004): Estimation of the Positional Uncertainty in Line Simplification in GIS. The Cartographic Journal, Vol.41, No. 1, 37–45.