Cross-references are links between parts from different manufacturers. For example, Manufacturer A can create a cross-reference for a brake disc to a brake disc from Manufacturer B. If a user then searches for the brake disc from Manufacturer B in the TecDoc Catalogue Web, the link to the brake disc from Manufacturer A will also be displayed. In the TecDoc Catalogue Web, this is made clear through the added text “found via comparison number”. Cross-references may be used by TecDoc data users in exactly this structure. Use in the reverse direction and the creation of one’s own cross-references are prohibited by the data user contract.