National Building Research Institute -Pretoria, ZA

Pretoria, Z.A.National B., 1980. Proceedings of the seminar on water supply and drainage services in developing countries = Verrigtinge van die seminaar oor watervoorsienings- en dreineringsdienste in ontwikkelende lande, Pretoria, South Africa: National Building Research Institute. Available at: https://www.ircwash.org/sites/default/files/71NBRI80-1098.pdf.