  We show the relationship between the mathematical framework used in recent
papers by H.C. Rosu, S.C. Mancas and P. Chen (2014) and the second-order
confluent supersymmetric quantum mechanics. In addition, we point out several
immediate generalizations of the approach taken in the latter references.
Furthermore, it is shown how to apply the generalized scheme to the Dirac and
to the Fokker-Planck equation.
