Updated continually. OAIster is a union catalog of digital resources. Access is provided by "harvesting" descriptive metadata (records) from digital collections using OAI-PMH (the Open Archives Initiative Protocol for Metadata Harvesting). Search by Title, Author/Creator, Subject, Language or Entire Record. Searches can also be limited by resource type (text, image, audio, video, dataset) and sorted by title, author, date and hit frequency. Results allow further limiting by data contributor (i.e., where the record was harvested from).