Levelt, Willem J. M. Language Production Group Levelt, MPI for Psycholinguistics, Max Planck Society;
Levelt_Formal_Grammars_Vol1_1974.pdf (Publisher version), 4MB
Levelt, W. J. M. (1974). Formal grammars in linguistics and psycholinguistics: Vol. I, An introduction to the theory of formal languages and automata. The Hague: Mouton Publishers.