United Nations Environmental Program. (1987). State of the Environment: The state of the world environment. United Nations Environmental Program.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিUnited Nations Environmental Program. State of the Environment: The State of the World Environment. Nairobi, Kenya: United Nations Environmental Program, 1987.
M.L.A (9 ম সংস্করণ) উদ্ধৃতিUnited Nations Environmental Program. State of the Environment: The State of the World Environment. United Nations Environmental Program, 1987.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.