SWKB and proper quantization conditions for translationally shape-invariant potentials Kamal Mahdi, Y. Kasri, Y. Grandati and A. Bérard Eur. Phys. J. Plus, 131 8 (2016) 259 Published online: 05 August 2016 DOI: 10.1140/epjp/i2016-16259-3