Srisongkham, S., & Photong, C. (2020). Ion Balance Measuring and Recording System for Air Ionizers: doi: 10.14456/mijet.2021.6. Engineering Access, 7(1), 36–42. retrieved from https://ph02.tci-thaijo.org/index.php/mijet/article/view/10.14456.mijet.2021.6