Simplifying XML Schema: Single-type approximations of regular tree languages, with Tomasz Idziaszek, Wim Martens, Frank Neven and Jan Paredaens, J. Comput. Syst. Sci. 79(6): 910-936 (2013)

Regular Expressions with Counting: Weak versus Strong Determinism, with Marc Gyssens, Wim Martens, SIAM J. Comput. 41(1): 160-190 (2012)

Succinctness of the Complement and Intersection of Regular Expressions, with Frank Neven, . ACM Trans. Comput. Log. 13(1): 4:1-4:19 (2012)

The dynamic complexity of formal languages, with Marcel Marquardt and Thomas Schwentick, ACM Trans. Comput. Log. 13(3): 19:1-19:36 (2012)

Succinctness of pattern-based schema languages for XML, with Frank Neven, J. Comput. Syst. Sci. 77(3): 505-519 (2011)

Optimizing the Region Algebra is PSPACE-complete, with Frank Neven, Inf. Process. Lett. 110(16): 639-643 (2010)

Succinctness of regular expressions with interleaving, intersection and counting. Theor. Comput. Sci. 411(31-33): 2987-2998 (2010)

Incremental XPath evaluation, with Henrik Björklund and Wim Martens, ACM Trans. Database Syst. 35(4): 29:1-29:43 (2010)

Learning Deterministic Regular Expressions for the Inference of Schemas from XML Data, with Geert Jan Bex, Frank Neven and Stijn Vansummeren, ACM Trans. Web 4(4): 14:1-14:32 (2010)

Optimizing Schema Languages for XML: Numerical Constraints and Interleaving, with Wim Martens and Frank Neven, SIAM J. Comput. 38(5): 2021-2043 (2009)