1. Barton, G.E.: On the complexity of ID/LP parsing 1. Comput. Linguist. 11(4), 205–218 (1985)
2. Berglund, M., Björklund, H., Högberg, J.: Recognizing shuffled languages. Technical Report UMINF 11.01, Computing Sci., Umeå University (2011), http://www8.cs.umu.se/research/uminf/index.cgi
3. Biegler, F., Daley, M., McQuillan, I.: On the shuffle automaton size for words. In: DCFS, pp. 79–89 (2009)
4. Lecture Notes in Computer Science;H. Björklund,2007
5. Bloom, S.B., Ésik, Z.: Axiomatizing shuffle and concatenation in languages. Information and Comptuation 139(1), 62–91 (1997)