An object reference is an implicitly- or explicitly-defined data item containing a value - an object reference value - that uniquely references an object for the lifetime of the object. Implicitly-defined object references are the predefined object references and object references returned from an object property, an object-view, an inline method invocation or a function. Explicitly-defined object references are data items defined by a data description entry specifying a USAGE OBJECT REFERENCE clause.
No two distinct objects have the same object reference value and every object has at least one object reference.