I. Rajiv Gand IN,
“National Drinking Water Mission : action plan 1989-1990”. Rajiv Gandhi National Drinking Water Mission, New Delhi, India, p. 16 p., 1989.
G. A. Bridger,
Water quality and treatment, vol. no. D3. Ratmalana, Sri Lanka: National Water Supply and Drainage Board, 1989, p. iv, 182 p.: fig., tab.