Note allows for the attachment of a piece of additional information to any object with an ID. Note facilitates capturing temporary processing notes such as "Review and approval required". A single note can be attached to multiple objects by reference to the objects. Note may also contain content for a needed object that has been reported for addition in a later version of the schema. Ideally this should be handled by a local extension, but Note can accommodate run-time extensions when required. The Note should be housed within the Maintainable object that contains the referenced objects. In this way the user is ensured of receiving all known Note attachments when the maintainable content is delivered. This means that if a Note references objects within multiple Maintainable objects, the Note should be repeated in each Maintainable and reference only those objects with that Maintainable.