V.A.2. Content-Incorporated [Optional*]
Contains identifiers of records incorporated into the content or the actual data contained in these records.

I.A.2. Transaction-Domain-Identifier [Mandatory]
Uniquely identifies the domain from which the record originated with sufficient specificity to identify the transaction-type and the organization responsible.

I.A.3. Transaction-Instance-Identifier [Mandatory]
Uniquely identifies a transaction instance with date, time and necessary sequence identifiers.

III.A.1.File-ID [Mandatory]
Identifies each file that makes up the record. This affords the ability for the system to bring together all of the parts to form the whole.