1) AHMED, S. A., M. ITO and K. UEKI: Water quality as affected by waterhyacinth decomposition after 2,4-D and ametryne application. Weed Res. (Japan) 25, 42-49 (1980).
2) American Public Health Association: Standard Methods for the Examination of Weter and Wastewater. 14th ed., Washington, D. C. (1975).