Ladder operators for subtle hidden shape invariant potentials
  Ladder operators can be constructed for all potentials that present the integrability condition known as shape invariance, satisfied by most of the exactly solvable potentials. Using the superalgebra of supersymmetric quantum mechanics we construct the ladder operators for two exactly solvable potentials that present a subtle hidden shape invariance. 
Elso Drigo Filho and Regina Maria Ricotta