Karthikeyan, P., et al. “Compactness Results on Integro-Differential Equations Involving $\Psi$-Hilfer Fractional Derivative”. Discontinuity, Nonlinearity, and Complexity, vol. 12, no. 3, Aug. 2026, pp. 631-42, https://doi.org/10.5890/DNC.2023.09.010.