In this paper we analyse open standards for supporting the reuse of OER in different knowledge domains based on a generic architecture for content federation and higher-order services. Plenty OER are available at different institutions. We face the problem that the mere availability of these resources does not directly lead to their reuse. To increase the accessibility we integrated existing resource repositories to allow educational practitioners to discover appropriate resources. On top of this content federation we build higher order services to allow re-authoring and sharing of resources. Open standards play an important role in this process for developing high-level services for lowering the thresholds for the creation, distribution and reuse of OER in higher education.