Chanida Sangsuri และ Natchanun Leepipatpiboon. (2010) Modification of QuEChERS method for determination of morphine and codeine in urine. Chulalongkorn University:ม.ป.ท.Chanida Sangsuri และ Natchanun Leepipatpiboon. 2010. Modification of QuEChERS method for determination of morphine and codeine in urine. ม.ป.ท.:Chulalongkorn University;Chanida Sangsuri และ Natchanun Leepipatpiboon. Modification of QuEChERS method for determination of morphine and codeine in urine. ม.ป.ท.:Chulalongkorn University, 2010. Print.