Kongkajun, N., S. Kuharuangrong, and P. Aungkavattana. “Development of Ferroelectric Thin Films and Composite Materials by Sol-Gel Process”. Science & Technology Asia, vol. 6, no. 2, Nov. 2015, pp. 44-56, https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/41868.