The Logic Resource Center base system. Features unsided binary rules, plain syntax, and the falsum. Allows both Fitch and Lemmon derivations.

The Logical System of the CMU Online Learning Inititiative. Features sided binary rules, Fitch assumption discharge, the falsum, and lots of parentheses.

The logical system of Bergman, Moor and Nelson's The Logic Book.

The original development logic of the Logic Resource Center based on the first generation `fol` parser. Features Reductio and DNE as the negation rules.

The Logic Resource Center base system LRC_F in Polish Notation.

Like the base system LRC_F, but allows open sentences