As we have seen, it is often necessary to introduce additional clauses into the Treaty in order to exclude tacit clauses or pre-contractual assurances or to include certain pre-contractual agreements. Otherwise, a simple misunderstanding could lead to costly litigation. The fact that two parties have knowingly and deliberately entered into contradictory agreements can only complicate the task of identifying the legitimate intention of their contracts. In a context where the legal relationship is so unclear, things can go wrong if the dispute is settled. It is therefore not in the best interest of the parties to undertake to comply with erroneous clauses. A typical comprehensive contractual clause could be as follows: „This letter is understood and shall be the final expression of the agreement concluded by the parties and constitutes a complete and exclusive statement of the conditions relating thereto, which supersedes all prior or written agreements or assurances and any other communication between the parties concerning the subject matter of this agreement.“ Questions relating to the effectiveness of entire contractual clauses seem to arise more and more frequently in disputes, in particular with regard to disputes related to long-term contracts such as joint ventures, long-term supply agreements, long-term financing agreements or amendments and/or renewals of such agreements or agreements for which the parties have had a long period of activity. . . .