Dyfyniad APA

Summary of the enviornmental report,1987. The council of enviornmental advisors,1987.

Dyfyniad Arddull Chicago

Summary of the Enviornmental Report,1987. Wisbaden: The council of enviornmental advisors,1987.

Dyfyniad MLA

Summary of the Enviornmental Report,1987. The council of enviornmental advisors,1987.

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