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(Rob) Agree, let's add only ValueType (not IValueDefinition) to avoid returning to old discussions 
(Jesper) But then you do not know the size of it either, hence you would need the spatial definition and time definition as well? I think a better solution would to include the IExchangeItem within the value set, if this kind of information is required. 
Meeting Decision: All agreed to the solution of adding only the ValueType to the IValueSet. Adding a reference to the IExchangeItem would force the developer to always create copies of the IExchangeItem since it is only a reference that can be updated.
Get/set multiple values from IValueSet
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