United Nations Environment Programme & United Nations Environment Programme. Governing Council. The State of the environment (Began in 1973.). United Nations Environment Programme.
Chicago-viite (17. p.)United Nations Environment Programme ja United Nations Environment Programme. Governing Council. The State of the Environment. Began in 1973. Nairobi, Kenya: United Nations Environment Programme.
MLA-viite (9. p.)United Nations Environment Programme ja United Nations Environment Programme. Governing Council. The State of the Environment. Began in 1973. United Nations Environment Programme.
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