.submodels[0].submodel_elements[0].value: Constraint AASd-121: For References the value of type of the first key of keys shall be one of Globally Identifiables.
.submodels[0].submodel_elements[0].value: Constraint AASd-122: For external references the value of type of the first key of keys shall be one of Generic Globally Identifiables.
.submodels[0].submodel_elements[0].value: Constraint AASd-124: For external references the last key of keys shall be either one of Generic Globally Identifiables or one of Generic Fragment Keys.