Cita APA (7a ed.)
Ehrlich, W. (2002). The twentieth century. University of Missouri Press.
Cita Chicago Style (17a ed.)
Ehrlich, Walter. The Twentieth Century. Columbia: University of Missouri Press, 2002.
Cita MLA (9a ed.)
Ehrlich, Walter. The Twentieth Century. University of Missouri Press, 2002.
Precaución: Estas citas no son 100% exactas.