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2. K.M. Sayre: Recognition: A Study in the Philosophy of Artificial Intelligence (U. Notre Dame Press, Notre Dame 1965)
3. W. Stallings: PhD Thesis, MIT (1971)
4. W. Stallings: “Computer Description and Recognition of Printed Chinese Characters”, SJCC (1972)
5. W. Stallings: Comp. Graphics Image Proc. 1, 47 (1972)