The following resources, guidelines, protocols, and projects are key items related to interoperability of Open Access repositories.

DINI Certificate for Document and Publication Services (2010) – A certificate that describes the technical, organizational, and legal aspects (including interoperability) that should be considered in setting up a scholarly repository service. Community – Digital Library Interoperability, Best Practices and Modelling Foundations.

DRIVER Project – A two-phase project that established both the organizational and technical infrastruture of a repository network in Europe, and produced several studies and the DRIVER Guidelines.

euroCRIS – The European Organization for International Research Information has been working on interoperability between CRISs (Current Research Information Systems), designed to store data about current research activity, grants, researchers, etc.  and Institutional Repositories.

Knowledge Exchange Usage Statistics Guidelines – Guidelines for the aggregation and exchange of usage data.

Open Archives Initiative – Object Reuse and Exchange (OAI-ORE) – Defines standards for aggregation of compound digital objects.

Open Archives Initiative – Protocol for Metadata Harvesting (OAI-PMH) – Protocol by which repositories allow for their metadata to be harvested and collected by other systems.

Publishing and the Ecology of European Research (PEER) – Project to “investigate the effects of large-scale, systematic depositing of authors’ final peer-reviewed manuscripts.”

PersID – Project to build a persistent identifier infrastructure for digital publications and electronic resources.

Resource Description Framework – A standard model for web-based data interchange.

Scholarly Output Notification and Exchange (SONEX) – An initiative supported by JISC to identify and analyze use cases for deposit of research papers into repositories.