1. Water. Quality Management Bureau. The water quality of the canals in Bangkok.; 1st ed.Bangkok:Water Quality Management Bureau; 2009.
2. American. Public Health Association. Standard Methods for the Examination of Water and Wastewater, American Water Works Association: Water Environment Federation, 1999. http://www.umass.edu/tei/mwwp/acrobat/sm9010-40intro.PDF.