Sergio Greco Domenico Saccà Carlo Zaniolo DATALOG Queries with Stratified Negation and Choice: from P to D<sup>P</sup>. 82-96 ICDT1995/P082.pdf 1995 ICDT db/conf/icdt/icdt95.html#GrecoSZ95 conf/icdt/95 http://dx.doi.org/10.1007/3-540-58907-4_8 conf/pods/AbiteboulSV90 journals/jcss/AbiteboulV91 conf/pods/AfratiCY91 books/mk/minker88/AptBW88 journals/jcss/ChandraH82 journals/jlp/ChandraH85 ... conf/iclp/GelfondL88 conf/dood/GiannottiPSZ91 conf/pods/GrecoZG92 journals/siamcomp/Immerman87 books/el/leeuwen90/Johnson90 books/el/leeuwen90/Kanellakis90 journals/iandc/Kolaitis91 journals/jcss/KolaitisP91 books/sp/Lloyd87 journals/jacm/MarekT91 books/cs/NaqviT89 ... ... conf/vldb/RamakrishnanSS92 journals/jcss/Sacca97 conf/pods/SaccaZ90 conf/pods/Schlipf90 ... books/cs/Ullman88 books/cs/Ullman89 journals/jlp/Gelder89 journals/jacm/GelderRS91 conf/stoc/Vardi82