Masoud, M. S.; Khalil, E. A. E.-M.; El Enein, S. A. E.-T. A.; Kamel, H. M. Solvatochromism and Potentiometic Studies of Some Active Nitroso- and Nitroso-Azo- Compounds. Eur. J. Chem. 2011, 2, 420-432.