The Issuing Authority is the organisation that produced the publication. This five-character code can be made up of numbers and upper-case letters. The specification recommends using a Commercial and Government Entity (CAGE) code [[5]] for the issuing authority, which happens to fit the criteria exactly. CAGE codes are widely used and many aerospace organisations, including airlines, are already using them, as was the case in the Knowledge Warehouse project. If in doubt there are various CAGE code search engines available online such as https://www.cagecode.info/.