Usage of reference identifier

When referencing internally (between model entities), we are unsure about how to use resource references. Since we want to refer to our internal models, and hence not use a URL but instead internal ids, we are unsure whether to use, reference.identifier.value or reference.reference. Are there any best practices?

Thanks in advance! isn’t for referencing at all - it’s so you can refer to the ‘reference’ element from elsewhere - typically from narrative or from Provenance.

Reference.reference is the preferred mechanism because search chaining, _include, _revinclude, etc. depend on Reference.reference. However, if the referenced content isn’t available for retrieval at a RESTful endpoint, then you can’t use Reference.reference

Reference.identifier is generally used when the referenced content doesn’t exist at a RESTful endpoint and so you specify a business identifier and leave it up to business logic/arbitrary business processes to figure out what record that actually means or how to resolve the reference.