GB 6730.37-1986 Methods for chemical analysis of iron ores; The 4-[(5-chloro-2-pyridyl)azo]-1,3-diaminobenzene photometric method for the determination of cobalt content
Methods for chemical analysis of iron ores; The 4-[(5-chloro-2-pyridyl)azo]-1,3-diaminobenzene photometric method for the determination of cobalt content