Sherpa Romeo is an online resource that aggregates and analyses publisher open access policies from around the world and provides summaries of publisher copyright and open access archiving policies on a journal-by-journal basis.

arXiv is a free distribution service and an open-access archive for 1,941,405 scholarly articles in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics.

OAIster is a union catalog of millions of records that represent open access resources. This catalog was built through harvesting from open access collections worldwide using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH).

This page lists parties that provide services based on metadata that is harvested using the OAI metadata harvesting protocol.

RECERCAT (Dipòsit de la Recerca de Catalunya) is a cooperative repository in which users can consult research literature from universities and research centers, such as articles, research works, final projects, congress talks, reports, working papers, etc. Documents can be directly sent to RECERCAT or via the repositories of each institution.

RECOLECTA, or Collector of Open Science, is the national aggregator of open access repositories. All Spanish digital infrastructures in which research results are published and / or deposited in open access are grouped together on this platform.

WorldWideScience.org is a global science gateway—accelerating scientific discovery and progress through a multilateral partnership to enable federated searching of national and international scientific databases and portals.

DIGITAL.CSIC organizes, preserves and disseminates CSIC research results in open access.

CSIC authors who wish to publish in OA benefit from total or partial financing from the APC (article processing charges) depending on the publisher.