GOST 23862.0-1979 Rare-earth metals and their oxides. General requirements for methods of analysis
GOST 23862.7-1979 Rare-earth metals and their oxides. Chemical-spectral methods of determination of impurities in oxides of rare-earth elements
GOST 23862.9-1979 Neodymium, gadolinium, terbium, holmium, erbium, thulium and their oxides. Chemical-spectral method of determination of impurities in oxides of rare-earth elements
GOST 5556-1981 Hygroscopic medical cotton wool. Specifications*, 1981-12-22 Update