Magnus 2012 – An Introduction to Formal Logic
Magnus, P. D. (2012). An Introduction to Formal Logic. Fecundity. https://open.umn.edu/opentextbooks/textbooks/54
Gimbel, S. (2016). Introduction to formal logic. Chantilly: The Teaching Company.
Gimbel, S. (2016). Truth-functional logic. Chantilly: The Teaching Company.
Gimbel, S. (2016). Truth tables. Chantilly: The Teaching Company.