1. The Theory of Parsing, Translation, and Compiling;Aho,1972
2. On formal properties of simple phrase structure grammars;Bar-Hillel;Z. Phonetik Sprachwiss. Kommunikat.,1961
3. Regular Algebra and Finite Machines;Conway,1971
4. The Mathematical Theory of Context-free Languages;Ginsburg,1966
5. AFL with the semilinear property;Ginsburg;J. Comput. System Sci.,1971