V. Shapiro, G. Gluhchev and D. Dimov, “Toward a Mul-tinational Car License Plate Recognition System,” Machine Vision Application, Vol. 17, No. 3, July 2006, pp. 173-183. doi:10.1007/s00138-006-0023-5
 V. Kamat and S. Ganesan, “An Efficient Implementation of the Hough Transform for Detecting Vehicle License Plates Using DSP’s,” Proceedings of Real Time Technology and Applications, Chicago, 15-17 May 1995, pp. 58-59. doi:10.1109/RTTAS.1995.516201
 Y. Yanamura, M. Goto and D. Nishiyama, “Extraction and Tracking of the License Plate Using Hough Transform and Voted Block Matching,” IEEE proceedings of Intelligent Vehicles Symposium, Columbus, 9-11 June 2003, pp. 243-246.
 C. N. E. Anagnostopoulos and I. E. Anagnostopoulos, “A License Plate Recognition Algorithm for Intelligent Transportation System Applications,” IEEE Transaction on Intelligent Transportation System, Vol. 7, No. 3, 2006, pp. 377-392.
 W. G. Zhu, G. J. Huo and X. Jia, “A Study of Locating Vehicle License Plate Based on Color Feature and Mathematical Morphology,” 6th International Conference on Signal Processing, Vol. 1, 2002, pp. 748-751.