VDI/VDE/DGQ 2618 Blatt 6.1-2008 Pruefmittelueberwachung - Anweisungen zur Ueberwachung von Messmitteln fuer geometrische Groessen - Pruefanweisung fuer Planglaeser und planparallele Pruefglaeser
Inspection of measuring and test equipment - Instructions to inspect measuring and test equipment for geometrical quantities - Test instruction for optical flats and optical parallels