Vivek, D., et al. “Dynamics and Stability Results for Nonlinear Neutral Pantograph Equations via Hilfer-Hadamard Fractional Derivative”. Discontinuity, Nonlinearity, and Complexity, vol. 8, no. 1, Aug. 2026, pp. 37-48, https://doi.org/10.5890/DNC.2019.03.004.