GB 6730.37-1986 Methods for chemical analysis of iron ores--The 4-[(5-chloro-2-phridyl)azo]-1,3-diamino-benzene photometric method for the determination of cobalt content (English Version)
2017GB/T 6730.37-2017 Iron ores—Determination of cobalt content—4-[(5-chloro-2-pyridyl)azo]-1,3-diamino-benzene spectrophotometric method
1986GB 6730.37-1986 Methods for chemical analysis of iron ores--The 4-[(5-chloro-2-phridyl)azo]-1,3-diamino-benzene photometric method for the determination of cobalt content