description: 'DSTU2: `DeviceMetric.source` (new:Reference(Device))' package_name: hl7.fhir.uv.xver-r2.r5 derivation: constraint name: ExtensionDeviceMetric_Source type: Extension elements: url: base: {max: '1', min: 1, path: Extension.url} pattern: {type: Uri, value: 'http://hl7.org/fhir/1.0/StructureDefinition/extension-DeviceMetric.source'} index: 0 value: base: {max: '1', min: 0, path: 'Extension.value[x]'} short: Describes the link to the source Device choices: [valueReference] index: 2 valueReference: short: Describes the link to the source Device refers: ['http://hl7.org/fhir/1.0/StructureDefinition/profile-Device-for-DeviceAssociation|0.1.0', 'http://hl7.org/fhir/StructureDefinition/DeviceAssociation|5.0.0'] type: Reference base: {max: '1', min: 0, path: 'Extension.value[x]'} choiceOf: value index: 3 package_version: 0.1.0 class: extension kind: complex-type url: http://hl7.org/fhir/1.0/StructureDefinition/extension-DeviceMetric.source base: http://hl7.org/fhir/StructureDefinition/Extension|5.0.0 version: 0.1.0 required: [url]