Shafiq, M.; Ullah Khan, I.; Zia-ur-Rehman, M.; Nadeem Asghar, M.; M. Asiri, A.; Nadeem Arshad, M. Synthesis and Antioxidant Activity of a New Series of 2,1-Benzothiazine 2,2-Dioxide Hydrazine Derivatives. ajc 2012, 24, 4799-4803.