title: a fast index for semistructured data. authors: brian cooper , gísli r. hjaltason , michael j. franklin , neal sample , moshe shadmon. venue: vldb. year: 2001.0
title: the x-tree : an index structure for high-dimensional data. authors: stefan berchtold , daniel a. keim , hans-peter kriegel. venue: very large data bases. year: 1996.0