User Story: As Implementer of a FHIR-based source data platform for clinical research, I need to be able to associate a Service Request with a Business Identifer for a Study in order to be able to explicitly associate corresponding Observations pertaining to my Study.

Acceptance Criteria:

• I am able to represent the Business Identifer for a Study in a ServiceRequest, allowing me to deterministically derive the relationship betwen a corresponding Observation and a ResearchStudy

Technical Story: In order to tie a ServiceRequest to a ResearchStudy, the extension intended for this purpose (http://build.fhir.org/extension-workflow-researchstudy.html) needs to include ServiceRequest in its list.

Zulip Discussion: https://chat.fhir.org/#narrow/stream/179290-research/topic/Associating.20Observations.20with.20a.20Trial/near/248469715