Não informado. (1973). Energy index. Environment Information Center, Energy Reference Department.
Chicagoスタイル(17版)引用形式Não informado. Energy Index. New York: Environment Information Center, Energy Reference Department, 1973.
MLA(8版)引用形式Não informado. Energy Index. Environment Information Center, Energy Reference Department, 1973.
警告: この引用は必ずしも正確ではありません.