Metadata Encoding and Transmission Standard
METS is an XML Schema designed for the purpose of creating XML document instances that express the hierarchical structure of digital library objects, the names and locations of the files that comprise those objects, and the associated metadata . METS can, therefore, be used as a tool for modeling real world objects, such as particular document types. The standard is maintained in the Network Development and MARC Standards Office of the Library of Congress, and is being developed as an initiative of the Digital Library Federation.