Dan A. Simovici Namita Singla Michael Kuperberg Metric Incremental Clustering of Nominal Data. 523-526 2004 conf/icdm/2004 ICDM http://csdl.computer.org/comp/proceedings/icdm/2004/2142/00/21420523abs.htm db/conf/icdm/icdm2004.html#SimoviciSK04