Narayan Venkatachalam, R. ., K. . Singh, and T. . Marar. “Phytochemical Screening and in Vitro Antioxidant Activity of Psidium Guajava”. Free Radicals and Antioxidants, vol. 2, no. 1, Dec. 2020, pp. 31-36, doi:10.5530/ax.2012.2.7.