فهرس المقالات Roya Derakhshani المقاله 1 - The investigation of loss aversion in investment companies in Tehran stock exchange 20.1001.1.25382217.2021.15.1.5.4 Zahra Madahi Roya Derakhshani Theory of Approximation and Applications , العدد 1 , السنة 15 , زمستان 2021