Ejikeme, C. L., M. O. Oyesanya, D. F. Agbebaku, and M. B. Okofu. “Discussing a Solution to Nonlinear Duffing Oscillator With Fractional Derivatives Using Homotopy Analysis Method (HAM)”. Theory and Practice of Mathematics and Computer Science Vol. 6 (February 6, 2021): 57–81. Accessed June 4, 2026. https://stm.bookpi.org/TPMCS-V6/article/view/59.