Yttrium, lanthanum, ytterbium, lutetium and their oxides. Chemical-spectral method of determination of impurities of vanadium, tungsten, iron, cobalt, manganese, copper, molybdenum, nickel, niobium, lead, tantalum, titanium and chromium
State system for ensuring the uniformity of measurements. Density of petroleum and petroleum products. Methods of calculation. Procedure and tables of calculation