فهرست مقالات level programming . Quadratic fractional programming . Fuzzy goal programming . Membership functions . Deviational variables دسترسی آزاد مقاله صفحه چکیده متن کامل 1 - An iterative method for tri-level quadratic fractional programming problems using fuzzy goal programming approach Semu Mitiku Kassa Teklay Hailay Tsegay