2015YS/T 569.4-2015 Methods for chemical analysis of thallium.Part 4:Determination of zinc content.Dithizone benzene spectrophotometry
2006YS/T 569.4-2006 Determination of zinc content in thallium (dithizone benzene extraction absorptiometry)
YS/T 569.4-2006 Determination of zinc content in thallium (dithizone benzene extraction absorptiometry) has been changed from GB/T 2592.4-1981 Thallium--Determination of zinc content--Dithizone extraction photometric method.