Churchill's , R. P. (1986). Study guide to accompany becoming logical an introduction to logic. St.Marin's Press.
Chicago-viite (17. p.)Churchill's , Robert Paul. Study Guide to Accompany Becoming Logical an Introduction to Logic. St.Marin's Press, 1986.
MLA-viite (9. p.)Churchill's , Robert Paul. Study Guide to Accompany Becoming Logical an Introduction to Logic. St.Marin's Press, 1986.
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