1. R. Zhang, P. -S. Tsai, J. E. Cryer and M. Shah: IEEE Trans. Pattern Anal. Mach. Intell. Vol. 21 (1999), p.690.
2. C. -W. Shu, in: Mathematics and Computation in Imaging Science and Information Processing, edtied by S. S. Goh, A. Ron, and Z. Shen World Scientific Publishing, Singapore (2007).
3. Y. -T. Zhang, H. -K. Zhao and S. Chen: Methods Appl. Anal. Vol. 13 (2006), p.299.
4. H. -K. Zhao: Math. Comp. Vol. 74 (2005), p.603.
5. A. H. Ahmed and A. A. Farag, in: Proc. The IEEE International Conference on Image Processing, San Antonio, TX (2007).