description: A reference to the authoritative, human readable, source of truth for the code system information. This extension has been deprecated due to being poorly defined. External code system information can be found in THO or the relevant HTA confluence pages. package_name: hl7.fhir.uv.extensions.r5 derivation: constraint name: CSAuthoritativeSource type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/codesystem-authoritativeSource'} index: 1 value: choices: [valueUri] index: 3 valueUri: {type: uri, choiceOf: value, index: 4} package_version: 5.2.0 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/codesystem-authoritativeSource base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.2.0 required: [valueUri, value]