Praphat Thanongkongsawad และ Varong Pavarajarn. (2005) Catalytic effects of metals on the formation of silicon nitride from rice husk ash via carbothermal reduction and nitridation process. Chulalongkorn University:ม.ป.ท.Praphat Thanongkongsawad และ Varong Pavarajarn. 2005. Catalytic effects of metals on the formation of silicon nitride from rice husk ash via carbothermal reduction and nitridation process. ม.ป.ท.:Chulalongkorn University;Praphat Thanongkongsawad และ Varong Pavarajarn. Catalytic effects of metals on the formation of silicon nitride from rice husk ash via carbothermal reduction and nitridation process. ม.ป.ท.:Chulalongkorn University, 2005. Print.