I am looking for a general formulation of the Fokker-Planck equation for diffusing particles in a general force field $F = -\nabla U + \nabla\times A$ in the overdamped regime (Smoluchowski equation).
So far I have only found literature taking $A=0$. The diffusion tensor could be isotropic - like for a diffusing sphere far from any boundaries. I would appreciate any hint/reference on that topic.