S-matrix for spin 1/2 particle in a Coulomb + Scalar potential
  The S-matrix for a spin 1/2 particle in the presence of a potential which is the sum of the Coulomb potential V_c=-A_1/r and a Lorentz scalar potential V_s= -A_2/r is calculated 
Arvind Narayan Vaidya and Luiz Eduardo Silva Souza (Rio de Janeiro   Federal University)