Mary F. Fernández Jan Hidders Philippe Michiels Jérôme Siméon Roel Vercammen Optimizing Sorting and Duplicate Elimination in XQuery Path Expressions. 554-563 2005 conf/dexa/2005 DEXA http://dx.doi.org/10.1007/11546924_54 db/conf/dexa/dexa2005.html#FernandezHMSV05