Maheswari, Muthukrishnan Latha, et al. “Multipoint Boundary Value Problem for a Coupled System of Psi-Hilfer Nonlinear Implicit Fractional Differential Equation”. Nonlinear Analysis: Modelling and Control, vol. 28, no. 6, Oct. 2023, pp. 1138-60, https://doi.org/10.15388/namc.2023.28.33474.