1. Vorozhtsov, N.N., The Fundamentals of Synthesis of Intermediate Products and Dyes (in Russian), Moscow: Goskhimizdat, 1955.
2. Venkataraman, K., Chemistry of Synthetic Dyes (in Russian), Leningrad: Goskhimizdat, 1956.
3. Ehrmann, K., VerfahrenzurHerstellung von aromatischen Aminosulfonsӓuren, Pat. 1233408 (BRD), 1967.
4. Svidchenko, V.F., Nikolaev, Yu.T., and Sokolsky, D.V., Sulfides of platinum metals as catalysts for reduction of nitrocompounds, Russ. J. Phys. Chem., 1973, vol. 47, p. 725.
5. Gait, R.J., Catalytic reduction of nitrobenzene sulphonic Acids. Pat. 1499589 (UK), 1978.