Wuttinan Lerkmangkorn และ Wanlapa Aeungmaitrepirom. (2006) Speciation analysis and preconcentration of chromium using chemically modified silica. Chulalongkorn University:ม.ป.ท.Wuttinan Lerkmangkorn และ Wanlapa Aeungmaitrepirom. 2006. Speciation analysis and preconcentration of chromium using chemically modified silica. ม.ป.ท.:Chulalongkorn University;Wuttinan Lerkmangkorn และ Wanlapa Aeungmaitrepirom. Speciation analysis and preconcentration of chromium using chemically modified silica. ม.ป.ท.:Chulalongkorn University, 2006. Print.