1. How Much Water is There on Earth?, (n.d.). https://www.usgs.gov/special-topic/water-science-school/science/how-much-water-there-earth?qt-science_center_objects=0#qt-science_center_objects (accessed June 6, 2021).
2. Water Scarcity and Drought in the European Union, 2010. www.usgcrp.gov (accessed June 6, 2021).
3. These Countries Are the Most at Risk From a Water Crisis, (n.d.). https://www.bloomberg.com/graphics/2019-countries-facing-water-crisis/(accessed June 6, 2021).
4. Australia's water crisis, intelligence and national security, (n.d.). https://www.iiss.org/blogs/analysis/2020/01/australia-water-crisis-intelligence-national-security (accessed June 6, 2021).
5. Sustainability: four billion people facing severe water scarcity;Mekonnen;Sci. Adv.,2016