T. K. Tran, L. H. Phung, H. N. le, T. T. H. Nguyen, X. S. Nghiem, and V. T. Pham, “A Dynamic Model for Ultrasonic – assisted Extraction of Bio-active Compounds from Natural Products”, ASEAN J. Chem. Eng., vol. 12, no. 2, pp. 35-42, Dec. 2012.