Singer, M. (1987). Passage to a human world. Hudson Institute.
Cita Chicago (17th ed.)Singer, Max. Passage to a Human World. Indianapolis, Ind.: Hudson Institute, 1987.
Cita MLA (8th ed.)Singer, Max. Passage to a Human World. Hudson Institute, 1987.
Atenció: Aquestes cites poden no estar 100% correctes.