Nadia Magvira, Khusnul Khatimah, Nursan Haryanto, Sarasrina, Nur Sipa, Serli Alifia, Suriani M. FORMATION OF AN EFFICIENT SYARIAH STOCK PORTFOLIO USING THE MARKOWITZ MODEL ON THE JAKARTA ISLAMIC INDEX. jiem [Internet]. 2026Jul.29 [cited 2026Aug.1];8(2):995-1003. Available from: https://jurnal.stmikiba.ac.id/index.php/jiem/article/view/453