Não informado. (1991). Environment watch. Cutter Information.
Chicagoスタイル(17版)引用形式Não informado. Environment Watch. Arlington, Mass: Cutter Information, 1991.
MLA(8版)引用形式Não informado. Environment Watch. Cutter Information, 1991.
警告: この引用は必ずしも正確ではありません.