1. P. Kilpeläinen, Tree Matching Problems with Applications to Structured Text Databases. PhD thesis, Deptartment of Computer Science, University of Helsinki, 1992.
2. S. Amer-Yahia, S. Cho, D. Srivastava, Tree pattern relaxation, in: Proceedings of the 8th International Conference on Extending Database Technology. LNCS 2287, Springer, 2002, pp. 496–513.
3. S. Amer-Yahia, N. Koudas, A. Marian, D. Srivastava, D. Toman, Structure and content scoring for XML, in: Proceedings of the 31st International Conference on Very Large Data Bases, 2005, pp. 361–372.
4. A. Marian, S. Amer-Yahia, N. Koudas, D. Srivastava, Adaptive processing of top-k queries in XML, in: Proceedings of the 21st International Conference on Data Engineering, 2005, pp. 162–173.
5. T. Schlieder, Schema-driven evaluation of approximate tree-pattern queries, in: Proceedings of the 8th International Conference on Extending Database Technology, LNCS 2287, Springer, 2002, pp. 514–532.