Peter Sander Specifying Operations for Nested Relations by Rules and Partial Orders. 44-58 MFDBS1991/P044.pdf 1991 MFDBS db/conf/mfdbs/mfdbs91.html#Sander91 conf/mfdbs/91 db/conf/mfdbs/Sander91.html journals/vldb/AbiteboulB95 conf/dbpl/AbiteboulG87 books/mk/minker88/AptBW88 journals/jcss/BancilhonK89 conf/icdt/Beeri88 conf/edbt/BeeriK90 conf/pods/BeeriNRST87 conf/dood/ChenC89 conf/dbpl/ChenKW89 conf/sigmod/GyssensG88 ... conf/pods/HullS89 conf/pods/KiferW89 conf/pods/Kuper87 conf/pods/Kuper88 books/sp/Lloyd87 journals/tods/RothKS88 journals/dke/Sander92 journals/is/SchekS86 ... books/cs/Ullman88 journals/jacm/EmdenK76