United Nations Environmental Program. (1987). State of the Environment: The state of the world environment. United Nations Environmental Program.
Citação do estilo Chicago (17ª ed.)United Nations Environmental Program. State of the Environment: The State of the World Environment. Nairobi, Kenya: United Nations Environmental Program, 1987.
Citação MLA (9ª ed.)United Nations Environmental Program. State of the Environment: The State of the World Environment. United Nations Environmental Program, 1987.
Nota: a formatação da citação pode não corresponder 100% ao definido pela respectiva norma.