@inproceedings{SIGMOD-2004-Ordonez,
	author        = "Carlos Ordonez",
	booktitle     = "{Proceedings of the 32nd ACM SIGMOD International Conference on Management of Data}",
	doi           = "10.1145/1007568.1007670",
	ee            = "http://www.sigmod.org/sigmod/sigmod04/eproceedings/pdf/I-002c.pdf",
	isbn          = "1-58113-859-8",
	pages         = "866--871",
	publisher     = "{ACM}",
	title         = "{Vertical and Horizontal Percentage Aggregations}",
	year          = 2004,
}