Here are some commonly used metadata mapping protocols:
- Crosswalks
- OAI-PMH (Open Archives Initiative Protocol for Metadata Harvesting)
- Z39.50
- SRU (Search/Retrieve via URL) and CQL (Contextual Query Language)
- OpenURL
- METS (Metadata Encoding and Transmission Standard)
- MODS (Metadata Object Description Schema)
- Dublin Core Metadata Element Set
- MARC (Machine Readable Cataloging)
- EAD (Encoded Archival Description)