(1) In maintaining the commercial records and the documentation otherwise required, the merchant is to use a living language. Where acronyms, numbers, letters of the alphabet or symbols are used, their meaning must be unequivocally defined in each individual case.
(2) The entries posted in the books and the documentation otherwise required must be complete, correct and timely and must be made in a structured manner.
(3) An entry or a documented record may not be modified such that it is no longer possible to establish its original content. Nor may any modifications be made that, by their nature, leave unclear whether they were already part of the entry or record originally or were made only at a later point in time.
(4) The commercial records and the documentation otherwise required may also consist of the structured collection of vouchers in a file, or of their structured storage on data carriers, provided that these forms of bookkeeping, including the procedure applied in this context, are in keeping with the principles of proper accounting. Where commercial records and the documentation otherwise required are maintained on data carriers, it must be ensured in particular that the data are available for the duration of the retention period and that they can be made readable at any time within a reasonable period of time. Subsections (1) to (3) apply accordingly.