The "F-diagram" was first proposed in a publication by Hesperian Foundation for the United Nations Development Programme (UNDP) in 2005 and has been widely used in many other sanitation publications since then.
The "F-diagram" was first proposed in a publication by Hesperian Foundation for the United Nations Development Programme (UNDP) in 2005. The "F-diagram" has been widely used in many other sanitation publications since then.