| Definition: A reference from an instance of a class in this ontology to an object in an external resource. Comment: As the most abstract xref class in the ontology, instances of the xref class should be created rarely, if ever. |
| •owl:Thing |
| •utilityClass |
| •externalReferenceUtilityClass |
| •xref |
| externalReferenceUtilityClass |
| ID MAX 1 |
| DB-VERSION MAX 1 |
| DB MAX 1 |
| ID-VERSION MAX 1 |
Class(xref partial externalReferenceUtilityClass
restriction(ID maxCardinality(1))
restriction(DB-VERSION maxCardinality(1))
restriction(DB maxCardinality(1))
restriction(ID-VERSION maxCardinality(1)))
DisjointClasses(xref dataSource
openControlledVocabulary
bioSource)