@inproceedings{SIGMOD-2004-RaoPZ,
	author        = "Jun Rao and Hamid Pirahesh and Calisto Zuzarte",
	booktitle     = "{Proceedings of the 32nd ACM SIGMOD International Conference on Management of Data}",
	doi           = "10.1145/1007568.1007643",
	isbn          = "1-58113-859-8",
	pages         = "671--682",
	publisher     = "{ACM}",
	title         = "{Canonical Abstraction for Outerjoin Optimization}",
	year          = 2004,
}