2-Naphthalenecarboxylic acid, 4-((9,10-dihydro-9,10-dioxo-1-anthracenyl)azo)-3-hydroxy- 4-((9,10-Dihydro-9,10-dioxo-1-anthryl)azo)-3-hydroxy-2-naphthoic acid 51867-75-5 EINECS 257-483-8