GB 223.49-1985 Methods for chemical analysis of iron,steel and alloy--The extraction separation-chlorophosphonazo mA photometric method for the determination of rare earth elements (English Version)
1994GB/T 223.49-1994 Methods for chemical analysis of iron,steel and alloy. Extraction separation-chlorophosphonazo mA spectrophotometric method for the determination of the total rare tarth content
1985GB 223.49-1985 Methods for chemical analysis of iron,steel and alloy--The extraction separation-chlorophosphonazo mA photometric method for the determination of rare earth elements
GB 223.49-1985 Methods for chemical analysis of iron,steel and alloy--The extraction separation-chlorophosphonazo mA photometric method for the determination of rare earth elements was changed to GB/T 223.49-1994 Methods for chemical analysis of iron,steel and alloy. Extraction separation-chlorophosphonazo mA spectrophotometric method for the determination of the total rare tarth content.