Naglaa Ragaa Saeid, Heba Sayed, Safwat Saadeldin Elsebaey, Hegazy Zaher,. “A Rough Set Theory Approach for Minimizing Insolvency Risk of Pension Fund”. Design Engineering (November 2, 2021): 9162-9176. Accessed April 29, 2024. http://www.thedesignengineering.com/index.php/DE/article/view/5962.