Dy, D.L. and Esguerra, J.P. 2005. Quantum systems with position-dependent effective mass and equispaced energy levels: New exact results and test of a perturbation scheme. Proceedings of the Samahang Pisika ng Pilipinas, 23(1), SPP-2005-2C-01. URL: https://proceedings.spp-online.org/article/view/SPP-2005-2C-01.