Symbolic logic & methods of deduction : (in his book Introduction to logic) / M. Irving Irving, M. French - Fiction. 160 IRS pp. 220-22, 228-29, 236-38, 242, 43, 249-56 s.l. : n.l., 0000 0000 Text pp. 220-22, 228-29, 236-38, 242, 43, 249-56 eng