Keine Buchung ohne Beleg. No booking without a receipt. It is a basic rule of German bookkeeping. Behind it stands § 238 of the Commercial Code. Every merchant must keep books that follow the principles of proper bookkeeping. The books must allow an expert third party to get an overview of the business within a reasonable time. Die Geschäftsvorfälle müssen sich in ihrer Entstehung und Abwicklung verfolgen lassen. Every transaction must be traceable from its origin to its completion.