The Gras conjecture in function fields by Euler systems
  We use Euler systems to prove the Gras conjecture for groups generated by Stark units in global function fields. The techniques applied here are classical and go back to Thaine, Kolyvagin and Rubin. We obtain our Euler systems from the torsion points of sign-normalized Drinfel'd modules. 
Hassan Oukhaba and St\'ephane Vigui\'e
math.NT