On simple Shamsuddin derivations in two variables
  We study the subgroup of $k$-automorphisms of $k[x,y]$ which commute with a simple derivation $D$ of $k[x,y].$ We prove, for example, that this subgroup is trivial when $D$ is a Shamsuddin simple derivation. In the general case of simple derivations, we obtain properties for the elements of this subgroup. 
R. Baltazar
math.AC