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.r4b derivation: constraint name: CSAuthoritativeSource type: Extension elements: extension: {index: 0} url: pattern: {type: uri, value: 'http://hl7.org/fhir/StructureDefinition/codesystem-authoritativeSource'} type: uri index: 1 value: choices: [valueUri] index: 3 valueUri: {type: uri, choiceOf: value, index: 4} package_version: 5.3.0-ballot-tc1 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/codesystem-authoritativeSource base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.3.0-ballot-tc1 required: [value, valueUri]