Extension All FHIR elements must have a @value or children Must have either extensions or value[x], not both Extension.id All FHIR elements must have a @value or children Extension.extension All FHIR elements must have a @value or children Must have either extensions or value[x], not both Extension.url All FHIR elements must have a @value or children f:Extension/f:valueCoding system: minimum cardinality of 'system' is 1 version: maximum cardinality of 'version' is 0 code: minimum cardinality of 'code' is 1 display: maximum cardinality of 'display' is 0 userSelected: maximum cardinality of 'userSelected' is 0 Extension.valueCoding All FHIR elements must have a @value or children Extension.valueCoding.id All FHIR elements must have a @value or children Extension.valueCoding.extension All FHIR elements must have a @value or children Must have either extensions or value[x], not both Extension.valueCoding.system All FHIR elements must have a @value or children Extension.valueCoding.version All FHIR elements must have a @value or children Extension.valueCoding.code All FHIR elements must have a @value or children Extension.valueCoding.display All FHIR elements must have a @value or children Extension.valueCoding.userSelected All FHIR elements must have a @value or children