@inproceedings{SIGMOD-1993-Guting,
	author        = "Ralf Hartmut Güting",
	booktitle     = "{Proceedings of the 23rd ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD93/P277.PDF",
	doi           = "10.1145/170035.170079",
	pages         = "277--286",
	publisher     = "{ACM Press}",
	title         = "{Second-Order Signature: A Tool for Specifying Data Models, Query Processing, and Optimization}",
	year          = 1993,
}