Koch, P. (2010). Water sources (4th ed.). American Water Works Association.
Chicago-referens (17:e uppl.)Koch, Paul. Water Sources. 4th ed. Denver, Colo.: American Water Works Association, 2010.
MLA-referens (9:e uppl.)Koch, Paul. Water Sources. 4th ed. American Water Works Association, 2010.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.