1. Shiklomanov I (1993) World fresh water resources. In: Gleick PH (ed) Water in crisis: a guide to the world’s fresh water resources. Oxford University Press, New York, pp 14–24
2. Perlman H (2016) Educational materials. https://water.usgs.gov/edu/watercycle.html
3. Evans J, Perlman H (2016) USGS educational materials. https://water.usgs.gov/edu/watercycle.html
4. Dowgiałło J, Karski A, Potocki I (1969) Geologia surowców balneologicznych. Wydawnictwa Geologiczne, Warszawa, p 296. [in Polish only]
5. Grünhut L, Hintz E (1907) Einteilung der mineralwässer. Deutsches Bäderbuch, Leipzig