The OWL ontology refset should represent essential information about an ontology, such as, namespaces, ontology URI, ontology version URI, and import statement.
Apart from the standard information for all OWL ontologies, any specific information of an ontology can be included. The OWL ontology refset enables the use of prefixes in the OWL axiom refset.

Namespaces

The namespace declarations cover the Standard Prefix Names for all ontologies with additional SNOMED CT specific prefix name. The prefix name "sct:" is for SNOMED CT concept identifiers. The namespace URI is http://snomed.info/id/.

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It is recommended to use the default prefix ":" to minimise the size and improve readability in the OWL refset. The prefix name "sct:" should be declared and used when http://snomed.info/id/ is not the default namespace.

Ontology URI and

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Version URI

The ontology URI and the version URI together identify a particular version of ontology. According to the convention, an ontology document should be accessible via the ontology URI if it is the current version. Since a release edition contains the current version of ontology, the ontology URI is sufficient for the OWL ontology refset. The version should be determined from the SNOMED CT release package. The version URI does not need to be included in the OWL ontology refset.  For example:

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Ontology(<http://snomed.info/sct/900000000000207008> <http://snomed.info/sct/900000000000207008/version/20180731>)

Edition,

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Modules and Ontology Import Statement

Each SNOMED CT Edition should be represented as a separate ontology based on the identifier of the most dependent module. The international release is represented by a single ontology and identified by the SNOMED CT core module id as the ontology URI. It includes two modules for terminology content excluding modules for derivatives:

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