Mungo, P., & Clough, B. (1992). Approaching zero: The extraordinary underworld of hackers, phreakers, virus writers, and keyboard criminals (1st American ed.). New York: Random House.MLA Citation
Mungo, Paul., and Bryan Clough. Approaching Zero: The Extraordinary Underworld of Hackers, Phreakers, Virus Writers, and Keyboard Criminals. 1st American ed. New York: Random House, 1992.