Alvarez-Castillo, D., and M. Kirchbach. “Exact Spectrum and Wave Functions of the Hyperbolic Scarf Potential in Terms of Finite Romanovski Polynomials”. Revista Mexicana De Física E, vol. 53, no. 2 Jul-Dec, Jan. 2007, pp. 143-54, https://rmf.smf.mx/ojs/index.php/rmf-e/article/view/4550.