Anderson, J. M., & Johnstone, H. W. (1962). Natural deduction: The logical basis of axiom systems. Wadsworth Pub.
Cita Chicago (17th ed.)Anderson, John Mueller, i Henry W. Johnstone. Natural Deduction: The Logical Basis of Axiom Systems. Belmont, Calif: Wadsworth Pub, 1962.
Cita MLA (9th ed.)Anderson, John Mueller, i Henry W. Johnstone. Natural Deduction: The Logical Basis of Axiom Systems. Wadsworth Pub, 1962.
Atenció: Aquestes cites poden no estar 100% correctes.