Ha Thi Thu Hoai, Nguyen Trong Nghia and Nguyen Thi Quynh Hoa 2022. PROCEDURE OPTIMIZATION FOR DETERMINATION OF PERFLUOROOCTANE SULFONIC ACID (PFOS) AND PERFLUOROOCTANOIC ACID (PFOA) IN PAPER – BASED FOOD PACKAGING SAMPLES. UTEHY Journal of Applied Science and Technology. 36, (Dec. 2022), 27-32.