References
- Salomaa , A. 1973 . Formal Languages , New York : Academic Press .
- P[acaron]un , Gh. 1984 . Recent Results in Problems in Formal Language Theory , Edited by: Enc , St. Bucharest : Academic Press . in Romanian
- Aho , A.V. and Ullman , J.D. 1972 . The Theory of Parsing, Translation and Compiling , Englewood Cliffs, N.J : Prentice-Hall . 1973
- Csuhaj-Varju E. Dassow J. On distributed grammar systems Inform. Sci. to appear