Halacy, D. S. (1971). Now or never: The fight against pollution. Four Winds Press.
Cita Chicago Style (17a ed.)Halacy, D. S. Now or Never: The Fight Against Pollution. New York: Four Winds Press, 1971.
Cita MLA (9a ed.)Halacy, D. S. Now or Never: The Fight Against Pollution. Four Winds Press, 1971.
Precaución: Estas citas no son 100% exactas.