1. Aho, A.V.: Indexed grammars - an extension of context-free grammars. J. ACM 15(4), 647–671 (1968)
2. Alur, R., Madhusudan, P.: Visibly pushdown languages. In: Proc. 36th Ann. ACM Symp. on Theory of Computing (STOC 2004), pp. 202–211. ACM Press, New York (2004)
3. Baader, F., Lutz, C., Turhan, A.-Y.: Small is again beautiful in description logics. KI – Künstliche Intelligenz (2010) (to appear)
4. Bar-Hillel, Y., Perles, M., Shamir, E.: On formal properties of simple phrase structure grammars. Zeitschrift für Phonologie, Sprachwissenschaft und Kommunikationsforschung 14, 113–124 (1961)
5. Barrett, C., Jacob, R., Marathe, M.: Formal-language-constrained path problems. SIAM Journal on Computing 30(3), 809–837 (2000)