<base_url>/CodeSystem eg https://ontoserver.csiro.au/stu3-latest/CodeSystem
(further discussion needed on distinction as to a) whether the code system is present on the server and b) whether it is possible to be used a the substrate for an expansion operation)
This page by CSIRO lists a number of servers and sends them requests for valueset expansions https://ontoserver.csiro.au/vstool/
Note: work needed on the Terminology Capabilities resource to properly answer this question.
TODO Link!
How should historical associations best be accessed?
How to do lookup and expand operations?
Watch that running this statement on any unix or mac command line will result in the dollar sign being interpreted as a variable (which probably doesn't exist!) and the URL will break at that point. Change the " to ' to avoid this.
```
curl --location --request GET "https://ontoserver.csiro.au/stu3-latest/ValueSet/$expand?url=http%253A%252F%252Fsnomed.info%252Fsct%252F32506021000036107%252Fversion%252F20160630%253Ffhir_vs%253Drefset%252F929360061000036106&_format=xml"
```
See Section 4.9.8.6 of the FHIR Specification - "Searching for codes in Value Sets" - at http://hl7.org/fhir/valueset.html. In the case of SNOMED CT, this would exclude any implicit FHIR Value Set that contains an edition and version of the Code System in its entirety.
Could reference set membership be a property of the code?
Source and Target are Valuesets and System is the CodeSystem of the code being looked up.
This question came up in relation to an implementer using the Global Patient Set (GPS) in a non-member country. The Code System Resource is required to ensure interoperability between licensed and non-licensed sites. In the later case, using the GPS, the Code System Content Mode should be set to fragment, to indicate that only a subset of the contents of the full Code System are included. However, the Code System URL of that fragment should still be http://snomed.info/sct.
Watch out for a URL for the Expand operation that contains an additional question mark (e.g. implicit Value Set syntax)
Could the TerminologyCapabilities statement be enhanced to specify which version of any particular computable language has been implemented?