get https://fhir-api.zapehr.com/r4b/DocumentReference/
DocumentReference on the FHIR specification website.
A reference to a document of any kind for any purpose. Provides metadata about the document so that the document can be discovered and managed. The scope of a document is any seralized object with a mime-type, so includes formal patient centric documents (CDA), cliical notes, scanned paper, and non-patient specific documents like policy text.