The inefficiency of single determinations of this AGB does not touch the validity of the remaining determinations. In place of an ineffectual determination, an effective economic and as approaching as possible regulation steps in place. Same applies to possible contingent contract spaces. The corrections of errors, especially of misspelling or miscalculation in written offers, confirmations of house boat-Berlin, remain reserve. Deviations, next to agreements, as well as additional-agreements must be held in writing.