Klein, P. D. (1981). Certainty: A refutation of sceptisim. University of Minnesota Press.
Cita Chicago (17th ed.)Klein, Peter D. Certainty: A Refutation of Sceptisim. University of Minnesota Press, 1981.
Cita MLA (9th ed.)Klein, Peter D. Certainty: A Refutation of Sceptisim. University of Minnesota Press, 1981.
Atenció: Aquestes cites poden no estar 100% correctes.