VDI/VDE/DGQ 2618 Blatt 6.1-2008 Inspection of measuring and test equipment - Instructions to inspect measuring and test equipment for geometrical quantities - Test instruction for optical flats and optical parallels
2009VDI/VDE/DGQ 2618 Blatt 6.1-2009 Inspection of measuring and test equipment - Test instruction for optical flats and optical parallels
2008VDI/VDE/DGQ 2618 Blatt 6.1-2008 Inspection of measuring and test equipment - Instructions to inspect measuring and test equipment for geometrical quantities - Test instruction for optical flats and optical parallels