This document describes mechanisms where interoperability of data is ensured with the use of standards. The standards we covered are both domain related, the archival standards in XML formats such as EAD, EAC-CPF and EAG, and transversal standards, whose use is recommended in the context of any digital project, in particular the ISO standards for the representation of language, script and countries. Interoperability of archival descriptions expressed in EAD is made possible with the specification of a specific EAD profile for EHRI. This profile is built and maintained using the TEI-ODD framework, which is explained of the first section of the report. Interoperability and reusability of EHRI resources is also ensured with the design of more consistent URLs, composed with standardised methods and using ISO reference codes. This design has to be seen as a first step through a persistent identifier system. The work initiated in WP11 and presented in this document will be continued, enhanced and developed by other EHRI work packages, WP7 Virtual Access to EHRI Virtual Observatory, WP10 Resource Identification and Integration Workflows and WP13 Research Data Infrastructures for Holocaust Material.