Supersymmetry and coherent states for the displacement-operator-derived effective mass system M. Vubangsi, M. Tchoffo, L. C. Fai and Yu. M. Pis’mak Eur. Phys. J. Plus, 130 1 (2015) 7 Published online: 16 January 2015 DOI: 10.1140/epjp/i2015-15007-7