@inproceedings{SIGMOD-1991-ImielinskiNV,
	author        = "Tomasz Imielinski and Shamim A. Naqvi and Kumar V. Vadaparty",
	booktitle     = "{Proceedings of the 21st ACM SIGMOD International Conference on Management of Data}",
	cdrom         = "SIGMOD91/P288.PDF",
	doi           = "10.1145/115790.115838",
	pages         = "288--297",
	title         = "{Incomplete Objects — A Data Model for Design and Planning Applications}",
	year          = 1991,
}