Consistency of the Born Approximation for the spin-1/2 Aharonov-Bohm   Scattering
  The relativistic scattering of a spin-1/2 particle from an infinitely long solenoid is considered in the framework of covariant perturbation theory. The first order term agrees with the corresponding term in the series expansion of the exact amplitude, and second order term vanishes, thus proving that Born approximation is consistent. 
M. Boz (Hacettepe) and N. K. Pak (METU)