Prevention of use and abuse of tax havens : exchange of information / Alfredo García Prats. - In: . - Sumário: I. Introduction A- Reasons for reconsidering the debate II. Identification of Tax Havens A- Impossibility to estabilish a general valid definition B- Elements identifying a 'tax haven' C- Use and abuse of tax havens III. Types of tax havens A- According to the use and tax avoided IV. Anti tax haven measures A- Consideration of fiscal competence B- Classification according to the legal source C- Classification according to the nature of the provision V. Complementary measures. The exchange of information A- Obstacles to effective action of exchange of information mechanisms in order to reduce tax evasion and avoidance through tax havens B- Suggestions for improvement Evasão Fiscal / Estímulo Fiscal / Direito Fiscal Internacional / Convenção Internacional / Convenção Fiscal / Direito à Informação / 351.713:341.1/.8 /