@ARTICLE{
        BN09,
        AUTHOR	  = "Benjamin Bustos and Gonzalo Navarro",
        TITLE	  = "Improving the space cost of k-NN search in metric spaces by using distance estimators",
        JOURNAL	  = "Multimedia Tools and Applications",
	VOLUME	  = "41",
	NUMBER	  = "2",
	PAGES	  = "215--233",
        PUBLISHER = "Springer",
	YEAR	  = "2009"
}