{"comparisonGroup":[{"concept":{"coding":[{"code":"placebo","display":"Placebo","system":"http://hl7.org/fhir/example-comparison-group"}]}},{"concept":{"text":"ap303"}}],"id":"example-crossover-placebo-to-drug","identifier":[{"value":"ecsr45"}],"period":{"start":"2022-06-10"},"resourceType":"ResearchSubject","status":"active","study":{"reference":"example-ctgov-study-record"},"subject":{"reference":"cfsb1676546565857"}}