@inproceedings{STOC-2009-BatsonSS,
	author        = "Joshua D. Batson and Daniel A. Spielman and Nikhil Srivastava",
	booktitle     = "{Proceedings of the 41st Annual ACM Symposium on Theory of Computing}",
	doi           = "10.1145/1536414.1536451",
	isbn          = "978-1-60558-506-2",
	pages         = "255--262",
	publisher     = "{ACM}",
	title         = "{Twice-ramanujan sparsifiers}",
	year          = 2009,
}