Frederiksen, H. D. (1992). Drought planning and water efficien-: Cy implications in water resources management. The World Bank.
Chicago-viite (17. p.)Frederiksen, Harald D. Drought Planning and Water Efficien-: Cy Implications in Water Resources Management. Washington D.C: The World Bank, 1992.
MLA-viite (9. p.)Frederiksen, Harald D. Drought Planning and Water Efficien-: Cy Implications in Water Resources Management. The World Bank, 1992.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.