Wolfram, S. (1989). Philosophical logic: An introduction. Routledge.
Chicago-čujuhus (17. p.)Wolfram, Sybil. Philosophical Logic: An Introduction. London: Routledge, 1989.
MLA-čujuhus (9. p.)Wolfram, Sybil. Philosophical Logic: An Introduction. Routledge, 1989.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.