del Rosario, A.L., Dela Cruz, C.J., Lumban, C. and Ramos, H.J. 2015. Optical emission spectroscopy of CH4:H2 plasma via DC hollow-cathode discharge facility. Proceedings of the Samahang Pisika ng Pilipinas, 33(1), SPP-2015-PB-28. URL: https://proceedings.spp-online.org/article/view/1234.