Algebraic derivation of spectrum of the Dirac Hamiltonian for arbitrary   combination of Lorentz-scalar and Lorentz-vector Coulomb potentials
  Spectrum of the Dirac Equation is obtained algebraically for arbitrary combination of Lorentz-scalar and Lorentz-vector Coulomb potentials using the Witten's Superalgebra approach. The result coincides with that, known from the explicit solution of Dirac equation. 
Tamar T. Khachidze and Anzor A. Khelashvili