P. S. I. P. W. Prince Sul Water,
“International journal of water resources and arid environments”. Prince sultan research center for environment, water and desert - King Saud University, Riyadh SA, Riyadh - SA.
D. General fo DGIS,
“Internationale samenwerking”. Netherlands, Ministry of Foreign Affairs, DGIS, Information Department, The Hague, The Netherlands.
“Introductory field note”. Water and Sanitation Program - African Region, Nairobi, Kenya.