K. Umam, F. W. Putro, G. Q. O. Pratamasunu, A. Z. Arifin, and D. Purwitasari, “COVERAGE, DIVERSITY, AND COHERENCE OPTIMIZATION FOR MULTI-DOCUMENT SUMMARIZATION”, Jurnal Ilmu Komputer dan Informasi, vol. 8, no. 1, pp. 1-10, Mar. 2015.