Dwi Saryanti, Dian Nugraheni, and Nisa Sindi Astuti, “Preparation and Characterization of Betel Leaves (Piper betle Linn) Extract Nanoparticle with Ionic Gelation Method”, J. Trop. Pharm. Chem., vol. 5, no. 1, pp. 15–20, Jun. 2020.