NeTEx is a CEN standard, the formal documents describing the standard are available as Technical Specifications (TS) from your national standardisation body. A fee in the national currency is charged for such documents by each standardisation body. However the actual formats and designs described by the TS may be used without charge, and without necessarily purchasing the CEN NeTEx publications. You may use the schema and models for free under a GPL license as described on NeTEx web site (http://netex-cen.eu/?page_id=20). This ensures that the IPR is in the public domain and may be safely considered as a long term strategic investment.