Não informado. (1973). Energy index. Environment Information Center, Energy Reference Department.
Chicago-Zitierstil (17. Ausg.)Não informado. Energy Index. New York: Environment Information Center, Energy Reference Department, 1973.
MLA-Zitierstil (8. Ausg.)Não informado. Energy Index. Environment Information Center, Energy Reference Department, 1973.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.