Montgomery, D. R. (2012). Dirt: The erosion of civilizations (New ed.). University of California Press.
Cita Chicago (17th ed.)Montgomery, David R. Dirt: The Erosion of Civilizations. New ed. Berkeley, Calif. ; London: University of California Press, 2012.
Cita MLA (9th ed.)Montgomery, David R. Dirt: The Erosion of Civilizations. New ed. University of California Press, 2012.
Atenció: Aquestes cites poden no estar 100% correctes.