statistics of Member States. ARTICLE 4 HARMONISATION OF VALUATIION LAWS AND PRACTICE Member States undertake to adopt a system of valuing goods for Customs purposes based on principles of transparency, equity, uniformity and simplification of application in accordance with the WTO Valuation System. ARTICLE 5 SIMPLIFICATION AND HARMONISATION OF CUSTOMS PROCEDURES 1. Member States, undertake to incorporate in their Customs Laws, provisions designed to simplify Customs procedures in accordance with internationally accepted standards, recommendations and guidelines particularly those which are contained in the International Instruments of: - the World Customs Organisation (WCO); - the United Nations Economic Commission for Europe (UN-ECE) - the International Maritime Organisation (IMO); - the International Civil Aviation Association (ICAO);