JPFA E. Introduction, Author Guidlines, and Table of Contents JPFA Vol 9 No 2 December 2019. J. Penelit. Fis. Apl. [Internet]. 2019Dec.31 [cited 2024May5];9(2):ii-vii. Available from: https://journal.unesa.ac.id/index.php/jpfa/article/view/7174