BGB Para. 765 et seq. (768) / Customs code of EU - Enforcement Regulation / TIR Convention (International Customs Convention of 14 November 1975 concerning International Carriage of Goods covered by the TIR Carnet / TIR Carnet) / Federated group giving guarantees / Guarantee obligation / Function of security guarantee and legislation / Failure to pay carnet / Abusive and fraudulent failure to pay carnet / Time limit and extension of time limit / Notification of collection / Enforcement of guarantee