If, within 5 years from the date of our description, you notify us in writing that the item is not genuine, as described in our physical description at the time of sale (unless otherwise qualified), we will refund the purchase price you originally paid. Our guarantee of authenticity does not apply if the exchange has evolved since the date of sale, which has led to a change in the generally accepted opinion of experts at the time of sale or to the knowledge of differences of opinion. The guarantee of authenticity is removed if the case can only prove to be authentic through a scientific procedure which, at the time of publication of the catalogue by the seller, was not available or generally recognized, was excessively expensive or impractical or which probably damaged the object. If the seller receives an order from the buyer for sale by the seller and the purchase of products by the buyer and this order is not a response to an offer from the seller or if the seller receives an order or acceptance by the buyer that differs from the seller`s offer, this order or acceptance is considered only a request for an offer. 5.2 You purchase all items on the basis of descriptions provided by us on our website, in our catalogues or elsewhere. The price and availability of items are subject to change without notice and all items are offered subject to prior sale. For books, the dimensions are indicated by the width of the book block and the disc brand or, if this is not possible, by the printing of cards and printouts. 10.6.