NameFlagsCard.TypeDescription & Constraintsdoco
.. DocumentReference 0..*US Core DocumentReference Profile
... identifier S0..1Identifier
... status S1..1codeBinding: DocumentReferenceStatus (required)
... type S1..1CodeableConceptBinding: Document Type Value Set (required)
... subject S1..1Reference(US Core Patient Profile)
... created S0..1dateTime
... indexed S1..1instant
... content S1..1BackboneElement
.... attachment S1..1Attachment
..... contentType S1..1code
..... url S1..1uri
.... format S0..1CodingBinding: DocumentReference Format Code Set (extensible)
... context S0..1BackboneElement
.... encounter S0..1Reference(US Core Encounter Profile)

doco Documentation for this format