Comment on "Analytic Solution of the Relativistic Coulomb Problem for a   Spinless Salpeter Equation"
  We demonstrate that the analytic solution for the set of energy eigenvalues of the semi-relativistic Coulomb problem reported by B. and L. Durand is in clear conflict with an upper bound on the ground-state energy level derived by some straightforward variational procedure. 
Wolfgang Lucha and Franz F. Sch\"oberl