Helmisyah, A., M. Ghazali, and S. Abdullah. “Characterisation of Thermal Barrier Coating on Piston Crown for Compressed Natural Gas Direct Injection (CNGDI) Engines”. Applied Science and Engineering Progress, vol. 5, no. 4, Aug. 2013, pp. 73-77, https://ph02.tci-thaijo.org/index.php/ijast/article/view/67315.