How is repetion of information avoided in GJXDM?
Reference elements exist to allow schema designs with multiple occurrences of the same information object or instance to reference a single content-filled object rather than to repeat it in different locations.
This ensures that the same information object does not repeat multiple times and mislead the receiver into thinking there are multiple (different) objects. If an object is recorded once and referenced from everywhere else it is used, then there is a lower risk of misunderstanding or inconsistency. This requires one XML element of type ReferenceType for each element in the model. That is, for every element named "X" in GJXDM, there is a second element named "XReference" that is intended to reference, or "point to", an element named X appearing elsewhere in the instance.
While this technique makes the GJXDM somewhat redundant, the use of separate elements for bearing content and content references makes it easier for applications to know immediately if and when they are looking at the information object itself or a reference to it.