conf/pods/89 Raghu Ramakrishnan Yehoshua Sagiv Jeffrey D. Ullman Moshe Y. Vardi Proof-Tree Transformation Theorems and Their Applications. 172-181 1989 PODS db/conf/pods/pods89.html#RamakrishnanSUV89 http://doi.acm.org/10.1145/73721.73739 db/conf/pods/RamakrishnanSUV89.html journals/anthology/cd1-3:PODS89/P172.PDF journals/anthology/dvd1:text/1-3/PODS89/P172.PDF conf/pods/BancilhonMSU86 conf/stoc/ChandraLM81 conf/stoc/ChandraM77 conf/pods/CosmadakisK86 conf/lics/GaifmanMSV87 conf/eds/IoannidisW88 journals/jlp/Ioannidis92 ... ... conf/sigmod/Naughton88 conf/pods/SaccaZ86 conf/pods/Sagiv87 conf/pods/Saraiya89 conf/pods/Shmueli87 books/cs/Ullman88 ...