H\"older estimates for non-local parabolic equations with critical drift
  In this paper we extend previous results on the regularity of solutions of integro-differential parabolic equations. The kernels are non necessarily symmetric which could be interpreted as a non-local drift with the same order as the diffusion. We provide an Oscillation Lemma and a Harnack Inequality which can be used to prove higher regularity estimates. 
Hector Chang-Lara and Gonzalo Davila
math.AP