Retnosari, R., Sari, K. K., Marfu’ah, S., Sutrisno, & Rachman, I. B. (2022). Assisted ultrasonic wave of vanillin derivatives synthesis and antioxidant activity using DPPH method. Communications in Science and Technology, 7(2), 181-187. https://doi.org/10.21924/cst.7.2.2022.963