S. Zhao, I. E. Ijaodoro, M. McGowan, and E. Alexov. Calculation of electrostatic free energy for the nonlinear Poisson-Boltzmann model based on the dimensionless potential. Journal of Computational Physics, Elsevier BV, volume 497, pages 112634, January 2024. Y. Shao, M. McGowan, S. Wang, E. Alexov, and S. Zhao. Convergence of a diffuse interface Poisson-Boltzmann (pb) model to the sharp interface pb model: a unified regularization formulation. Applied Mathematics and Computation, volume 436, pages 127501, 2023. C. Li, M. McGowan, E. Alexov, and S. Zhao. A Newton-like iterative method implemented in the DelPhi for solving the nonlinear Poisson-Boltzmann equation [J]. Mathematical Biosciences and Engineering, volume 17, issue 6, pages 6259-6277, 2020.