Steve Lawrence Frans Coetzee Gary William Flake David M. Pennock Robert Krovetz Finn Årup Nielsen Andries Kruger C. Lee Giles Persistence of information on the web: Analyzing citations contained in research articles. 235-242 2000 conf/cikm/2000 CIKM http://doi.acm.org/10.1145/354756.354824 db/conf/cikm/cikm2000.html#LawrenceCFPKNKG00