Mauricio Minuto Espil Alejandro A. Vaisman Efficient Intensional Redefinition of Aggregation Hierarchies in Multidimensional Databases. 2001 DOLAP http://www.cis.drexel.edu/faculty/song/DOLAP2001/Espil%20-%201.pdf db/conf/dolap/dolap2001.html#EspilV01