Aoying Zhou Weining Qian Hailei Qian Clustering DTDs: An Interactive Two-Level Approach. 807-819 2002 17 J. Comput. Sci. Technol. 6 http://jcst.ict.ac.cn/cone/cone26.html#paper16 db/journals/jcst/jcst17.html#ZhouWQ02