References
- Day , P. H. and Shyr , H. J. 1983 . Languages defined by some partial orders . Soochow J. Math. , 9 : 53 – 62 .
- De Luca , A. 1982 . On the Combinatorial Problems in Free Monoids . Discrete Mathematics , 38 : 207 – 225 .
- Hopcroft , John E. and Ullman , Jeffrey D. 1969 . Formal Languages and their Relation to Automata , Addison-Wesley, Massachusetts .
- Yong-Yie Lin Properties of Words and the Related Homomorphisms Master Thesis, Institute of Applied Mathematics, Chung-Yuan Christian University Chung-Li, Taiwan 1995
- Lyndon , R. C. and Schützenberger , M. P. 1962 . The equation a M =b N c p in a free group . Michigan Math. J. , 9 : 289 – 298 .
- Shyr , H. J. 1991 . Free Monoids and Languages , Second Edition , Taichung, , Taiwan : Hon Min Book Company .
- Shyr H. J. n Two Languages that Commute, Notes on Semigroups K. Marx. University Budapest 1983 257 269
- Shyr , H. J. and Thierrin , G. 1977 . Proceedings of 1997 Inter. FCT-Conference . Disjunctive Languages and Codes, Fundamentals of Computation Theory . 1977 , Poznan, Poland. pp. 171 – 176 . Springer-Verlag . Lecture Notes in the Computer Science No. 56
- Wood , D. 1987 . Theory of Computation , New York : Harper and Row .
- Wood , D. 1972 . A Factor Theorem for Subsets of a Free Monoid . Information and Control , 21 ( 1 ) : 21 – 26 .
- Yu , S. S. Factorization in the Monoid of Languages , Submitted for publication .