DOIs and HDLs  are persistent identifiers for digital objects. If a paper/dataset has a DOI or an HDL (handle) this information goes in the 0247 field, with the identifier type in the ‘2’ subfield and the identifier string in the ‘a’ subfield. The source of the DOI is automatically added to the ‘9’ subfield if it is available. If the DOI is for an erratum, addendum, previous version ($$qversion), etc., this information is added to the ‘q’ subfield (full listing here: https://inspire-schemas.readthedocs.io/en/latest/schemas/records/elements/material.html).

You may see an identifier string appended to a url, such as http://dx.doi.org/10.1016/j.nima.2015.10.029 or http://hdl.handle.net/11245/1.484470. The first part of the url resolves the identifier when it is being handled as a link to a web page. Only use the identifier string without the initial part of the url when cataloging in INSPIRE (see the table above). The identifier will appear as a link in the brief and detailed formats of the record and will resolve based on the tag you use in the ‘2’ subfield.

It is unnecessary to include a link in 8564 to the same page to which the identifier resolves.