1. Aho, A.V., Ullman, J.D.: The Theory of Parsing, Translation and Compiling, Volume I: Parsing. Prentice-Hall, New Jersey (1972)
2. Aho, A.V., Lam, M.S., Sethi, R., Ullman, J.D.: Compilers: Principles, Techniques, and Tools, 2nd edn. Addison-Wesley, Boston (2006)
3. Baker, B.S.: Non-context-free grammars generating context-free languages. Inf. Control 24(3), 231–246 (1974)
4. Cannon, R.L.: Phrase structure grammars generating context-free languages. Inf. Control 29(3), 252–267 (1975)
5. Cojocaru, L., Mäkinen, E.: On the complexity of Szilard languages of regulated grammars. Technical report, Department of Computer Sciences, University of Tampere, Tampere, Finland (2010)