3-Hydroxy-4-(2-hydroxy-1-naphtylazo)-7-nitro-1-naphthalenesulfonic acid

3-hydroxy-4-[(2-hydroxynaphthyl)azo]-7-nitronaphthalene-1-sulphonic acid

3-Hydroxy-4-[(2-hydroxy-1-naphtyl)azo]-7-nitronaphthalene-1-sulfonic acid

3-Hydroxy-4-[(2-hydroxy-1-naphthalenyl)azo]-7-nitro-1-naphthalenesulfonic acid