A.C. Kumoro, D.H. Wardhani, D.S. Retnowati, K. Haryani, S. Yustika, T.A. Fajar, Extraction of Essential Oil from Ultrasound Pre-treated Citronella Grass (cymbopogon Nardus) Leaves by Hydro-distillation Method, Chemical Engineering Transactions. 87 (2021) 643-648. doi:10.3303/CET2187108.