%0 Journal Article %T Existence de F-cristaux avec structures supplementaires %A Jean-Pierre Wintenberger %J Mathematics %D 2003 %I arXiv %X In this article, we prove under some hypothesis of non ramification, a conjecture of Kottwitz and Rapoport giving the existence of crystals with additional structures. %U http://arxiv.org/abs/math/0303026v1