(Naphthalin-sulfonsaeure-(1))-(4 azo 2)-(naphthol-(1)-sulfonsaeure-(4)), 2-(4-sulpho-1-naphthylazo)-1-naphthol-4-sulphonic acid, 4-Hydroxy-3,4'-azo-bis-naphthalin-1-sulfonsaeure, 4-Hydroxy-3-(4-sulfo-naphthalen-1-ylazo)-naphthalene-1-sulfonic acid, 1'-Hydroxy-[1.2']azonaphthalin-disulfonsaeure-(4.4'), 4-hydroxy-3-[(4-sulfo-1-naphthyl)azo]naphthalene-1-sulfonic acid, 2-(4-sulfo-1-naphthylazo)-1-naphthol-4-sulfonic acid