23It is settled law that the exemptions provided for by Article 13 of the Sixth Directive constitute independent concepts of Community law whose purpose is to avoid divergences in the application of the VAT system as between one Member State and another (see Case 348/87Stichting Uitvoering Financiële Acties [1989] ECR 1737, paragraph 11, and Case C-349/96CPP [1999] ECR I-973, paragraph 15) and must be placed in the general context of the common system of VAT (see, to that effect, Case 235/85Commission v Netherlands [1987] ECR 1471, paragraph 18).