Siahaan, G. G. Y., & Siagian, J. (2018). THE ANALYSIS OF OPTIMAL PORTFOLIO 3 COMPANIES’ STOCK AND THE INNOVATION OF STOCK PORTFOLIO, PERIOD OF 2014-2016. Fundamental Management Journal, 3(1), 25 - 31. Retrieved from http://ejournal.uki.ac.id/index.php/jm/article/view/718