Zimmerman, E. W. (1964). Introduction to world resources. Harper & Row.
Lua i Stíl Chicago (17ú heag.)Zimmerman, Erich Walter. Introduction to World Resources. New York: Harper & Row, 1964.
Lua MLA (9ú heag.)Zimmerman, Erich Walter. Introduction to World Resources. Harper & Row, 1964.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.