The logic engine on which Deductions is built is system-agnostic, which provides a great deal of flexibility. The following textbooks are already configured in Preferences, but you can also select custom language, symbol and rule parameters to get Deductions working how you want!
An Accessible Introduction to Mathematical Logic (Website)
Tony Roy, California State University, San Bernardino
A Modern Formal Logic Primer (Website)
Paul Teller, University of California, Davis
The Logic Book, 5th Ed. (Amazon)
Merrie Bergmann, Moor, Nelson: McGraw-Hill, 2008
Logics (Amazon)
John Nolt: Wadsworth, 1996
Symbolic Logic (Amazon)
Dale Jacquette: Wadsworth, 2000
A Concise Introduction to Logic, 10th ed. (Amazon)
Patrick Hurley: Wadsworth, 2008
Introduction to Logic, 13th ed. (Amazon)
Irving M. Copi, Cohen: Prentice-Hall, 2008
Logic and Philosophy: A Modern Introduction, 11th ed. (Amazon)
Alan Hausman, Kahane, Tidman: Wadsworth, 2009
The Power of Logic, 4th ed. (Amazon)
Frances Howard-Snyder, Snyder, Wasserman: McGraw-Hill, 2008
Modern Logic (Intuitionist) (Amazon)
Graeme Forbes: Oxford, 1994
nLab (Minimal) (Website)
I. Johansson, 1936