1. Phrase structure Languages, finite machines and channel capacity;Banerji;Information and Control,1963
2. On certain formal properties of grammars;Chomsky;Information and Control,1959
3. Finite state languages;Chomsky;Inform. Contr.,1958
4. The Mathematical Theory of Context-free Languages;Ginsburg,1966
5. On the entropy of context-free languages;Kuich;Information and Control,1970