| 18904 | 'Predicable' terms come in charged pairs, with one the negation of the other [Sommers, by Engelbretsen] |
| 18895 | Logic which maps ordinary reasoning must be transparent, and free of variables [Sommers] |
| 19053 | Logic would be more natural if negation only referred to predicates [Dummett] |
| 13916 | Term logic uses expression letters and brackets, and '-' for negative terms, and '+' for compound terms [Engelbretsen/Sayward] |
| 18907 | Term logic rests on negated terms or denial, and that propositions are tied pairs [Engelbretsen] |