@inproceedings{SIGMOD-2014-ZaschkeZN,
	author        = "Tilmann Zäschke and Christoph Zimmerli and Moira C. Norrie",
	booktitle     = "{Proceedings of the 32nd ACM SIGMOD International Conference on Management of Data}",
	doi           = "10.1145/2588555.2588564",
	isbn          = "978-1-4503-2376-5",
	pages         = "397--408",
	publisher     = "{ACM}",
	title         = "{The PH-tree: a space-efficient storage structure and multi-dimensional index}",
	year          = 2014,
}