http://hl7.org/fhir/StructureDefinition/DocumentReference|4.0.1

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.
element_idtypes
DocumentReference
DocumentReference.masterIdentifier
DocumentReference.identifier
DocumentReference.status
DocumentReference.docStatus
DocumentReference.type
DocumentReference.category
DocumentReference.subject
DocumentReference.date
DocumentReference.author
DocumentReference.authenticator
DocumentReference.custodian
DocumentReference.relatesTo
DocumentReference.relatesTo.code
DocumentReference.relatesTo.target
DocumentReference.description
DocumentReference.securityLabel
DocumentReference.content
DocumentReference.content.attachment
DocumentReference.content.format
DocumentReference.context
DocumentReference.context.encounter
DocumentReference.context.event
DocumentReference.context.period
DocumentReference.context.facilityType
DocumentReference.context.practiceSetting
DocumentReference.context.sourcePatientInfo
DocumentReference.context.related
DocumentReference
DocumentReference.id
DocumentReference.meta
DocumentReference.implicitRules
DocumentReference.language
DocumentReference.text
DocumentReference.contained
DocumentReference.extension
DocumentReference.modifierExtension
DocumentReference.masterIdentifier
DocumentReference.identifier
DocumentReference.status
DocumentReference.docStatus
DocumentReference.type
DocumentReference.category
DocumentReference.subject
DocumentReference.date
DocumentReference.author
DocumentReference.authenticator
DocumentReference.custodian
DocumentReference.relatesTo
DocumentReference.relatesTo.id
DocumentReference.relatesTo.extension
DocumentReference.relatesTo.modifierExtension
DocumentReference.relatesTo.code
DocumentReference.relatesTo.target
DocumentReference.description
DocumentReference.securityLabel
DocumentReference.content
DocumentReference.content.id
DocumentReference.content.extension
DocumentReference.content.modifierExtension
DocumentReference.content.attachment
DocumentReference.content.format
DocumentReference.context
DocumentReference.context.id
DocumentReference.context.extension
DocumentReference.context.modifierExtension
DocumentReference.context.encounter
DocumentReference.context.event
DocumentReference.context.period
DocumentReference.context.facilityType
DocumentReference.context.practiceSetting
DocumentReference.context.sourcePatientInfo
DocumentReference.context.related