Albrecht Schmidt 0002 Martin L. Kersten Menzo Windhouwer Querying XML Documents Made Easy: Nearest Concept Queries. 2001 conf/icde/2001 ICDE db/conf/icde/icde2001.html#SchmidtKW01 321-329 http://doi.ieeecomputersociety.org/10.1109/ICDE.2001.914844