1. Extensible Markup Language (XML) 1.1 (Second Edition) [Online May, 2011]. Available: http://www.w3.org/TR/xml11/
2. INitiative for the Evaluation of XML Retrieval (INEX) [Online May, 2011]. Available: https://inex.mmci.uni-saarland.de/
3. Kamps J (2009) Indexing units. In: Liu L, Tamer Özsu M (ed) Encyclopedia of database systems (EDS). Springer, Heidelberg
4. Kamps J, de Rijke M, Sigurbjörnsson B (2005) The importance of length normalization for XML retrieval. Inform Retrieval 8(4):631–654
5. Geva S (2005) GPX – Gardens point XML information retrieval. INEX 2004. Advances in XML information retrieval. Third International Workshop of the Initiative for the Evaluation of XML, Springer Verlag, Berlin, Heidelberg, Vol. 3977, pp 211–223