A Characterization of Jacobians by the Existence of Picard Bundles
  Based on the Matsusaka-Ran criterion we give a criterion to characterize when a principal polarized abelian variety is a Jacobian by the existence of Picard bundles. 
Ana Cristina L\'opez Mart\'in, Ernesto Carlo Mistretta, Dar\'io   S\'anchez G\'omez