On solution of Klein-Gordon equation in scalar and vector potentials
  Based on the Coulomb gauge, the accurate Klein-Gordon equation in static scalar and vector potentials was derived from Klein-Gordon equation in electromagnetic environment. The correct equation developed in this comment demonstrates that so-called the Klein-Gordon equation with scalar and vector potentials is incorrect; therefore, some papers published to solve Klein-Gordon equation with equal scalar and vector potential are also wrong. 
Liu Changshi
physics.gen-ph