Elke Achtert Christian Böhm Hans-Peter Kriegel Peer Kröger Online Hierarchical Clustering in a Data Warehouse Environment. 10-17 2005 conf/icdm/2005 ICDM http://doi.ieeecomputersociety.org/10.1109/ICDM.2005.111 db/conf/icdm/icdm2005.html#AchtertBKK05