AFIFY, A. E.-M. M.; SHALABY, E. A.; EL-BELTAGI, H. S. Antioxidant Activity of Aqueous Extracts of Different Caffeine Products. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, v. 39, n. 2, p. 117-123, 21 Nov. 2011.