the algebra of logic with special reference to Whitehead and Russell’s Principia mathematica (1932m)
Solomon Feferman, John W Dawson, Stephen Cole Kleene, Gregory Martin Moore, Robert M Solovay, Jean van HEIJENOORT · 2001
Abstract Two new axiom systems for the calculus of classes (propositional calculus) are specified. The first employs addition (a+ b) and complementation (a’) as primitive notions, and, in addition to the commutativity and associativity of+, requires only the following two axioms: