1. Visscher JT, Paramasivam R, Raman A. Slow sand filtration for community water supply: planning, design, construction, operation and maintenance. The Hague: International Reference Centre for Community Water Supply (IRC); 1987.
2. Amy G, Carlson K, Collins RM, et al. Integrated comparison of biofiltration in engineered versus natural systems. In: R Gimbel, JD Graham, MR Collins, editor. Mülheim: IWA; 2006. p. 3–11.
3. A toolkit for monitoring and evaluating household water treatment and safe storage programs. Geneva: WHO Press; 2012.