1. Ang, T., Brzozowski, J.: Languages convex with respect to binary relations, and their closure properties. Acta Cybernet. 19, 445–464 (2009)
2. Birget, J.C.: Intersection of regular languages and state complexity. ACM SIGACT News 22(2), 49 (1980)
3. Bordihn, H., Holzer, M., Kutrib, M.: Determination of finite automata accepting subregular languages. Theoret. Comput. Sci. 410, 3209–3249 (2009)
4. Brzozowski, J.: Derivatives of regular expressions. J. ACM 11, 481–494 (1964)
5. Brzozowski, J.: Quotient complexity of regular languages. In: Dassow, J., Pighizzini, G., Truthe, B. (eds.) 11th International Workshop on Descriptional Complexity of Formal Systems. pp. 25–42. Otto-von-Guericke-Universität, Magdeburg (2009),
http://arxiv.org/abs/0907.4547