C. H. U. N. D. P. /World Geneva,
“TDR news”. TDR Communications, World Health Organization, Geneva, Switzerland.
Technical Advisory Paper. New York, NY, USA: UNDP (United Nations Development Programme).
“Technical information / GATE”. German Appropriate Technology Exchange (GATE) /Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ), Eschborn, Germany.
Technical Manual Series on Rural Water Supply and Sanitation. Colombo, Sri Lanka: NORAD, Norwegian Agency for Development Cooperation.