1. Natural and anthropogenic factors affecting the groundwater quality in Serbia
2. WWDR. (2015). Water for a sustainable wrold. Retrieved October 25, 2020, from UNESCO: http://www.unesco.org/new/fileadmin/MULTIMEDIA/HQ/SC/images/WWDR2015Facts_Figures_ENG_web.pdf
3. Worldometer. (2020). Countries in the world by population (2020). Retrieved October 14, 2020, from Worldometer: https://www.worldometers.info/world-population/population-by-country/
4. Islandii. (2020, September 30). Thoddoo. Retrieved October 14, 2020, from Islandii: https://www.islandii.com/thoddoo/#:∼:text=Thoddoo%20is%20a%20fairly%20large,island%20is%20about%201400%20people.
5. Drinking Water Nitrate and Human Health: An Updated Review