Azam, M. S., M. Shafiquzzaman, I. Mishima, and J. Nakajima. “Measurement of Soluble Arsenic in Soil of Bangladesh by Acid-Alkali Sequential Extraction”. Journal of Scientific Research, vol. 1, no. 1, Dec. 2008, pp. 92-107, doi:10.3329/jsr.v1i1.1058.