Guozhu Dong Leonid Libkin Limsoon Wong 140-154 ICDT1997/P140.pdf 1997 ICDT db/conf/icdt/icdt97.html#DongLW97 conf/icdt/97 http://dx.doi.org/10.1007/3-540-62222-5_42 books/aw/AbiteboulHV95 journals/sigact/AbiteboulK90 ... conf/vldb/Albert91 ... journals/tcs/BunemanNTW95 conf/pods/ChaudhuriV93 journals/tcs/ConsensM93 conf/dbpl/DongLW95 ... journals/iandc/DongS95 conf/pods/DongS95 ... ... journals/iandc/FaginSV95 ... conf/sigmod/GriffinL95 journals/jcss/GrumbachM96 ... journals/tcs/GrumbachT95 journals/jacm/Klug82 conf/dbpl/LibkinW93 conf/pods/LibkinW94 journals/ipl/LibkinW95 journals/tods/OzsoyogluOM87 journals/tods/ParedaensG92 conf/pods/PatnaikI94 journals/jcss/Wong96