A universally unique identifier (UUID) is a 128-bit label used for information in computer systems. The term globally unique identifier (GUID) is also used.
OIDs that need to be referenced from other files like a Study OID could be represented with an UUID or other mechanism that renders a unique ID (e.g., ClinicalTrials.gov Identifier of the study “ClinicalTrials.gov.NCT12345678”; NASDAQ’s #: (“nasdaq<#>/STUDYXYZ”).