@inproceedings{SIGMOD-1987-Freytag,
	author        = "Johann Christoph Freytag",
	booktitle     = "{Proceedings of the 17th ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD87/P173.PDF",
	doi           = "10.1145/38713.38735",
	pages         = "173--180",
	title         = "{A Rule-Based View of Query Optimization}",
	year          = 1987,
}