Martin, P., E. Castro, and J. Paz. “Multi-Point Quasi-Rational Approximants for the Energy Eigenvalues of Two-Power Potentials”. Revista Mexicana De Física, vol. 58, no. 4, Jan. 2012, pp. 301-7, https://rmf.smf.mx/ojs/index.php/rmf/article/view/3926.