Cytotoxic effect of n-hexane insoluble fraction obtained from kloroform extract of kembang bulan leaves [Tithonia diversifolia (Hemsley) A. Gray] on HeLa cells and mechanism detection by Hoechst 33342 - Perpustakaan UGM, i-lib ([Yogyakarta] : Universitas Gadjah Mada, 2007)