Henk Ernst Blok Menzo Windhouwer Roelof van Zwol Milan Petkovic Peter M. G. Apers Martin L. Kersten Willem Jonker Flexible and scalable digital library search. 705-706 http://www.vldb.org/conf/2001/P705.pdf 2001 conf/vldb/2001 VLDB db/conf/vldb/vldb2001.html#BlokWZPAKJ01