M. R. Putri, N. J. P. Simanjuntak, and N. B. Sembiring, “Antioxidant Activity Test of Patchouli Leaf Ethanol Extract Lotion (Pogostemon Cablin Benth) Using The DPPH (2,2-Diphenyl-1-Picrylhydrazil) Method ”, JPS, vol. 9, no. 2, pp. 1725–1734, Jun. 2026.