1. Arruda Ayda, I. 1989. Aspects of the historical development of paraconsistent logic. In Paraconsistent logic: Essays on the inconsistent, ed. G. Priest, R. Routley, and J. Norman, 99–129. Nunchen/Handen/Wien: Philosophia Verlag.
2. Asenjo, F.G. 1996. Natural 3-valued logics: Characterization and proof theory. Notre Dame Journal of Formal Logic 7 (1): 103–106.
3. Avron, A. 1991a. Natural 3-valued logics: Characterization and proof theory. Journal of Symbolic Logic 56: 276–294.
4. Avron, A. 1991b. Simple consequence relations. Information and Computation 92: 105–139.
5. Batens, D. 1981. A completeness-proof method for extensions of the implicational fragment of the propositional calculus. Notre Dame Journal of Formal Logic 21 (3): 509–517.