@article {3671,
	title = {SP-GiST: An Extensible Database Index for Supporting Space Partitioning Trees},
	journal = {Journal of Intelligent Information Systems (JIIS)},
	volume = {17},
	year = {2001},
	pages = {215--240},
	doi = {10.1023/A:1012809914301},
	author = {Walid G. Aref and Ihab Ilyas}
}
