Tuan, Le Ngoc, and Pham Ngoc Chau. “OPTIMIZATION OF THE EFFICACY OF SLUDGE ULTRASONIC PRETREATMENT: A REVIEW”. <i>Vietnam Journal of Science and Technology</i>, vol. 52, no. 3, July 2014, pp. 373-88, doi:10.15625/0866-708X/52/3/2961.