Nattapon Srisittipokakun, Chittra KedKaew, Jakrapong Kaewkhao, Treedej Kittiauchawal, Kheamrutai Thamaphat, and Pichet Limsuwan. 2009. “Electron Spin Resonance (ESR) and Optical Absorption Spectra of a Manganese Doped Soda-Lime-Silicate Glass System”. Agriculture and Natural Resources 43 (5). Bangkok, Thailand:360-64. https://li01.tci-thaijo.org/index.php/anres/article/view/244843.