Abdullah, D.Kh., et al. “The Quadratic B-Spline Method for Approximating Systems of Volterra Integro Fractional-Differential Equations Involving Both Classical and Fractional Derivatives”. Bulletin of the Karaganda University. Mathematics Series, vol. 120, no. 4, Dec. 2025, pp. 5-20, doi:10.31489/2025m4/5-20.