1. Asveld, P. R. J. (2006). Generating all permutations by context-free grammars in Chomsky normal form. Theoretical Computer Science, 354(1), 118–130.
2. Bach, E. (1981). Discontinuous constituents in generalized categorial grammars. In North east linguistics society (NELS 11) (pp. 1–12).
3. Becerra-Bonache, L. (2006). On the learnability of mildly context-sensitive languages using positive data and correction queries. Ph.D. thesis, Universitat Rovira i Virgili, Tarragona, Spain.
4. Lecture notes in computer science;L. Becerra-Bonache,2004
5. Becker, T., Rambow, O., & Niv, M. (1992). The derivational generative power of formal systems or scrambling is beyond LCFRS (Tech. Rep. 92–38). Institute For Research in Cognitive Science, University of Pennsylvania.