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- https://clinicaltrials.gov/ct2/show/NCT12345678 (refereing to referring to a study registry reference)
- http://snomed.info/ns/concept/24762387 (refering to referring to an external concept in the SNOMED vocabulary)
- https://loinc.org/78200-3/ (refering to referring to an external concept in the LOINC vocabulary)
The preference is to use persistent URIs for these contexts (ie URIs i.e. URIs that should exist so any future references can be followed and understood).
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