description: Points to a preceding event within a workflow that was a prerequisite for or provides other justification for the current action. package_name: hl7.fhir.uv.extensions derivation: constraint name: FollowOnOf type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/workflow-followOnOf'} index: 1 value: choices: [valueReference] index: 3 valueReference: {type: Reference, choiceOf: value, index: 4} package_version: 5.3.0-ballot extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/workflow-followOnOf base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.3.0-ballot required: [valueReference, value]