Pengwichai, P., W. Sunthonkanokpong, and S. Maunsaiyat. “A SET OF LABORATORY LESSON ON AMPLIFIERS FOR A VOCATIONAL EDUCATION CERTIFICATE AUDIO EQUIPMENT COURSE”. Journal of Industrial Education, vol. 18, no. 1, June 2019, pp. 153-9, https://ph01.tci-thaijo.org/index.php/JIE/article/view/157040.