1. van der Hoek W, Hassan MUl, Ensink JHJ, Feenstra S, Raschid-Sally L, Munir S, et al. Urban Wastewater: A Valuable Resource for Agriculture: a Case Study from Haroonabad, Pakistan’. Research Report 63, Colombo, Sri Lanka. International Water Management Institute. 2002. pp 2–5.
2. Drechsel P, Graefe S, Sonou M, Cofie O. Informal irrigation in urban West Africa: An overview, Research Report 102, International Water Management Institute, Colombo, Sri Lanka. 2006
3. Andoh L. Helminth contamination of lettuce and associated risk factors at production sites, markets, and street food vendor sites in urban and peri-urban Kumasi. [M.Sc thesis presented to the Department of Theoretical and Applied Biology], Kwame Nkrumah University Science and Technology. Kumasi. 2008
4. WHO (World Health Organization). Guidelines for the safe use of wastewater, excreta and grey water: Wastewater use in agriculture (Volume 2). Report of a WHO Scientific Group. WHO Technical Report Series 778. World Health Organization, Geneva, Switzerland. 2006. pp 74–219.
5. Wastewater Reclamation and Reuse: Water Quality Management Library;T Asano,1998