UNEP. (2002). Global environment outlook 3. Earthscan.
Cita Chicago (17th ed.)UNEP. Global Environment Outlook 3. London: Earthscan, 2002.
Cita MLA (9th ed.)UNEP. Global Environment Outlook 3. Earthscan, 2002.
Atenció: Aquestes cites poden no estar 100% correctes.