The Economist Intelligence Unit. (1999). Best practices: Environment. Univerties Press.
Cita Chicago (17th ed.)The Economist Intelligence Unit. Best Practices: Environment. India: Univerties Press, 1999.
Cita MLA (8th ed.)The Economist Intelligence Unit. Best Practices: Environment. Univerties Press, 1999.
Atenció: Aquestes cites poden no estar 100% correctes.