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The DAI is the number after info:eu-repo/dai/nl/ .
info:eu-repo/dai/nl/ is just an authority namespace, telling the user or machine that the number is a DAI originating from the Netherlands.
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For the MODS metadata an extension has been made. The XML shema of the extension can be found here: http://purl.org/SURFREP/DAIdai-extension.xsd
For the use of this extension in MODS see: Use of MODS
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