Postel, S. (2005). Liquid assets: The critical need to safeguard freshwater ecosystems. Washington, D.C: Worldwatch Institute.
Chicago-tyylinen lähdeviittausPostel, Sandra. Liquid Assets: The Critical Need to Safeguard Freshwater Ecosystems. Washington, D.C: Worldwatch Institute, 2005.
MLA-viitePostel, Sandra. Liquid Assets: The Critical Need to Safeguard Freshwater Ecosystems. Washington, D.C: Worldwatch Institute, 2005.
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