1. The water footprint of humanity
2. World Health Organization drinking water https://www.who.int/en/news-room/fact-sheets/detail/drinking-water(accessed: April 2020).
3. United Nations Sustainable Development Groups Goals 6: Ensure access to water and sanitation for all https://www.un.org/sustainabledevelopment/water-and-sanitation/(accessed: April 2020).
4. WWAP (UNESCO World Water Assessment Programme) The United Nations World Water Development Report 2019 Leaving No One Behind2019.
5. H.Ritchie M.Roser Clean Water. Our World in Data2019.