GB/T 18115.13-2010
Chemical analysis methods of rare earth impurities in rare earth metals and their oxides.Part 13:Thulium.Determination of lanthanum,cerium,praseodymium,neodymium,samarium,europium,gadolinium,terbium,dysprosium,holmium,erbium,ytterbium,lutetium and yttrium (English Version)