Foundation references modeled as annotations on string-valued annotations

[samsontu]

In the OWL version of the WHO-FIC Foundation, exclusions (and, according to ICD Schema documentation, some index terms) are string-valued annotations, but have references to Foundation entities that are modeled as annotations on annotations. These references are probably not accessible on Protege forms.

[samsontu]

In the case inclusions, the values can be strings or inclusion terms from descendants, modeling inclusions as strings annotations that has its own entity-valued annotation allows the WHO-FIC OWL ontology to use a single property to model both situations. In the Protege 3 content model, the range of baseInclusion is the union of BaseInclusionTerm and SubclassInclusionTerm. Can we model inclusions as either entity URI or strings? (Alpha thalassaemia is an example of an category that has subclass inclusions.)