GOST R 8.641-2008 State sysem for ensuring the iniformity of measurements. State verification scheme for measuring instruments of the water solutions ion content by electrochemical methods (pX measuring instruments)
2013GOST R 8.641-2013 State system for ensuring the iniformity of measurements. State verification scheme for measuring instruments of the water solutions ion content by electrochemical methods (pX measuring instruments)
2008GOST R 8.641-2008 State sysem for ensuring the iniformity of measurements. State verification scheme for measuring instruments of the water solutions ion content by electrochemical methods (pX measuring instruments)