1. P.V.C. Hough, Method and means for recognizing complex patterns, U.S. patent 3 069 654, 1962.
2. A survey of the Hough transform;Illingworth;Comp. Vision Graph. Im. Proc.,1988
3. Machine Vision: Theory, Algorithms, Practicalities;Davies,1990
4. Generalizing the Hough transform to detect arbitrary shapes;Ballard;Pattern Recognition,1991
5. Generalized Hough transform for natural shapes;Samal;Pattern Recognition Letters,1997