description: This cross-version extension represents EvidenceVariable.characteristic.definitionReference from http://hl7.org/fhir/StructureDefinition/EvidenceVariable|5.0.0 for use in FHIR R4. package_name: hl7.fhir.uv.xver derivation: constraint name: Ext_R5_EvidenceVariable_ch_definitionReference type: Extension elements: url: base: {max: '1', min: 1, path: Extension.url} pattern: {type: Uri, value: 'http://hl7.org/fhir/5.0/StructureDefinition/extension-EvidenceVariable.characteristic.definitionReference'} index: 0 value: base: {max: '1', min: 0, path: 'Extension.value[x]'} short: Defines the characteristic (without using type and value) by a Reference choices: [valueReference] index: 2 valueReference: base: {max: '1', min: 0, path: 'Extension.value[x]'} type: Reference short: Defines the characteristic (without using type and value) by a Reference choiceOf: value index: 3 package_version: r5.r4-0.0.1-snapshot-2 class: extension kind: complex-type url: http://hl7.org/fhir/5.0/StructureDefinition/extension-EvidenceVariable.characteristic.definitionReference base: http://hl7.org/fhir/StructureDefinition/Extension|4.0.1 version: 0.0.1-snapshot-2 required: [url]