GB/T 18115.3-2006
Chemical analysis methods of rare earth impurities in rare earth metals and their oxides Praseodymium.Determination of lanthanum,cerium,neodymium,samarium,europium,gadolinium, terbium,dysprosium,holmium,erbium,thulium, ytterbium, lutetium and yttrium cont (English Version)