Zain, Z. A., N. S. M. Mussafi, and E. D. Supandi. “CLUSTER ANALYSIS OF K-MEANS AND WARD METHOD IN FORMING A ROBUST PORTFOLIO: AN EMPIRICAL STUDY OF JAKARTA ISLAMIC INDEX”. BAREKENG: Jurnal Ilmu Matematika Dan Terapan, Vol. 19, no. 1, Jan. 2025, pp. 537-46, doi:10.30598/barekengvol19iss1pp537-546.