Herman, Kevin, and Judi Prajetno Sugiono. “Studi Pengukuran Kekerasan Benda Dengan Analisa Spektral”. Journal of Informatics Development 1, no. 2 (April 30, 2023): 65–74. Accessed April 17, 2026. http://178.128.120.64/index.php/jid/article/view/1091.