1. Visual pattern recogniifion by moment invariants;Hu;IRE Trans. Information Theory IT-8,1962
2. Digital Pattern Recognition by Moments, Optical Character Recognition;Alt,1962
3. Designing Pattern Categorizers with Extremal Paradigm Information, Methodologies of Pattern Recognition;Lambert,1969
4. Moment normalization of handprinted characters;Casey;IBM J. Rcs. Develop,1970