References on the irrigation and drainage systems in Namibia ?

1. Namibia Ministry of Agriculture, Water and Forestry. (2016). National Irrigation Master Plan for Namibia. Retrieved from: http://www.mawf.gov.na/documents/irrigation/National%20Irrigation%20Master%20Plan%20for%20Namibia.pdf

2. Namibia Water Corporation (NamWater). (n.d.). Irrigation and Drainage. Retrieved from: https://www.namwater.com.na/irrigation-and-drainage/

3. Namibia Statistics Agency. (2018). Namibia Census of Agriculture 2013/2014: Irrigation and Drainage. Retrieved from: https://nsa.org.na/wp-content/uploads/2018/10/Namibia-Census-of-Agriculture-2013-2014-Irrigation-and-Drainage.pdf

4. Namibia Institute of Agricultural Research and Development. (2017). Irrigation and Drainage Systems in Namibia. Retrieved from: http://www.niared.org.na/irrigation-and-drainage-systems-in-namibia/

5. Namibia Agricultural Union. (2019). Irrigation and Drainage in Namibia. Retrieved from: https://www.nau.com.na/irrigation-and-drainage-in-namibia/