1. A. Rosenfeld, “ Quadtrees and Pyramids for pattern recognition and image processing”, Proc. 5th Int. Conf. on Pattern Recognition, Miami Beach, 1–4 Dec 1980, 802–811.
2. G.M. Hunter, “Linear transformation of pictures represented by Quadtree”, Comput. Graphics Image Processing, vol 10, no 3, July 1979, 289–296.
3. M. Imme, “A new method for edge detection”, IEE 3rd Int. Conf. on Image processing and its applications, Number 307, University of Warwick, U.K., 18–20 July 1989, 656–659.
4. A. Klinger, “Pattern and search statistics”, Optimised Methods in Statistics, J.S. Ustagi,ed., Academic Press, New York 1971.
5. H. Samet, “Connected component labelling using quadtrees”, J. ACM., vol 28, no 3, 1981, 487–501.