Open access describes free, unrestricted online access to research outputs such as journal articles and books. OA content is open to all, with no access fees. Open Access databases or collections are curated by the individual or organization that has created them. Many college and universities, scholarly societies, and non-profit organizations have created useful Open Access collections.
Note: Some resources are available only through the end of the academic year through publisher kindness in the face of classes transitioning to online learning. Those sources are in a separate box from the ones that are always free.