conf/vldb/94 Jürgen Frohn Georg Lausen Heinz Uphoff Access to Objects by Path Expressions and Rules. 273-284 1994 VLDB db/conf/vldb/vldb94.html#FrohnLU94 db/conf/vldb/vldb94-273.html VLDB94/P273.PDF conf/sigmod/AbiteboulB91 books/mk/BancilhonDK92 journals/jlp/ChenKW93 journals/tois/FishmanBCCCDDHKLMNRS87 conf/icde/GardarinV92 conf/vldb/Kim89 conf/sigmod/KiferKS92 journals/jacm/KiferLW95 journals/jcss/KiferW93 books/cs/NaqviT89 conf/dood/BusscheV93 conf/sigmod/Zaniolo83