2.2.7.1 External Reference Consumers
Within the formula, only certain formula elements (section 2.2.2.6) can contain external references. These specific formula elements (section 2.2.2.6) contain an XtiIndex structure (section 2.5.198.119) specifying an XTI (section 2.5.344), which in turn specifies the location and type of the external reference data. Only the following Ptg structures (section 2.5.198.25) can be external reference consumers:
PtgRef3d (section 2.5.198.85)
PtgRefErr3d (section 2.5.198.87)
PtgArea3d (section 2.5.198.28)
PtgAreaErr3d (section 2.5.198.30)
PtgNameX (section 2.5.198.77)