Velsen, J.A. van

van Velsen, J.A., 1990. Water reservoirs for the water supply schemes in Al Bayda Province (design, calculations and recommendations), (Technical note / Rada Integrated Rural Development Project no. 40) Arnhem, The Netherlands: Ilaco. Available at: https://es.ircwash.org/sites/default/files/217-90WA-8687.pdf.