A. N. Putri, N. Laila, and D. Forestryana, “Formula Optimization of Annona muricata Folium Ethanolic Extract of Anti Acne Gel Formulation using Factorial Design Method”, Borneo J Pharm, vol. 2, no. 2, pp. 63–70, Nov. 2019, doi: 10.33084/bjop.v2i2.981.