1. F. Bao, Limited Error-Propagation, Self-Synchronization and Finite Input Memory FSMs as Weak Inverses, Advances in Chinese Computer Science, Vol.3, World Scientific, Singapore, 1991, 1–24.
2. F. Bao, Composition and Decomposition of Weakly Invertible Finite Automata, Science in China, Vol.23, No.7, 1993, 759–766; also presented on the Fifth Asian Logic Conference, Singapore, June 13–15, 1993.
3. S. Even, Generalized Automata and Their Information Lossless, in Switching Circuit Teory and Logical Design, 1962, 144–147.
4. S. Even, On Information Lossless Automata of Finite Order, IEEE Trans. on Electronic Computers, Vol.14, No.4, 1965, 561–569.
5. D.A. Huffman, Canonical Forms for Information-lossless Finite State Logical Machines, IRE Trans. on Circuit Theory, 1959, May, 6, Special Supplement, 41–59.