Wenyuan Li Wee Keong Ng Ying Liu Kok-Leong Ong Enhancing the Effectiveness of Clustering with Spectra Analysis. 887-902 2007 19 IEEE Trans. Knowl. Data Eng. 7 http://dx.doi.org/10.1109/TKDE.2007.1066 db/journals/tkde/tkde19.html#LiNLO07