[CP03] P. Ciaccia, W. Penzo. The Collection Index to Support Complex Approximate Queries on XML Documents. Proc. of the First Int. XML Database Symposium (XSym 2003), Berlin, Germany, 2003.

[CP02a] P. Ciaccia, W. Penzo. Adding Flexibility to Structure Similarity Queries on XML Data. In Proc. of the 5th Int. Conf. on Flexible Query Answering Systems (FQAS 2002), Copenhagen, Denmark, 2002.

[CP02] P. Ciaccia, W.Penzo. Relevance Ranking Tuning for Similarity Queries on XML Data. Proc. of the First VLDB Workshop on Efficiency and Effectiveness of XML Tools and Techniques (EEXTT 2002), Hong Kong, China, 2002.

[Pen02] W. Penzo. Integration of Semantic and Structure Similarity for XML Data Ranking. Atti del X Convegno Nazionale su Sistemi Evoluti per Basi di Dati (SEBD 2002), Portoferraio, Italy, 2002.