فهرس المقالات Fractional calculus \sep Variable-order fractional derivative \sep Fractional differential equations حرية الوصول المقاله صفحة الملخص نص كامل 1 - An Efficient Numerical Approach for Approximating Nonlocal Variable-Order Weakly Singular Integro-Differential Equations Nayereh Tanha Behrouz Parsa Moghaddam Mousa Ilie