When construction work in Germany is paid by the hour, the VOB/B requires a paper trail. The contractor must announce hourly work before it begins. Then he submits Stundenlohnzettel, lists of hours, materials and equipment, daily or weekly according to custom. The client must return the certified lists within six working days at the latest. Objections can be written on the sheet or sent separately. Nicht fristgemäß zurückgegebene Stundenlohnzettel gelten als anerkannt. Sheets not returned in time count as accepted.