title: the a-tree : an index structure for high-dimensional spaces using relative approximation. authors: masatoshi yoshikawa , shunsuke uemura , yasushi sakurai , haruhiko kojima. venue: vldb. year: 2000.0
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