Belnap, N. D. (1977): "A useful four-valued logic", in: J. M. Dunn, G. Epstein (eds.). Modern Uses of Multiple-Valued Logic. Reidel, Dordrecht, 8-37.
Belnap, N. D. (1977): "How a computer should think", in: G. Ryle (ed.) ContemporaryAspects of Philosophy. Oriel Press, Stockfield, 30-56.
Béziau, J-Y., “New Light on the Square of Oppositions and its Nameless Corner”, Logical Investigations, 10 (2003), 218–233.
Caton, C. E. (1963). A Stipulation of a Modal Propostional Calculus in Terms of Modalized Truth-Values. Notre Dame Journal of Formal Logic , IV (3).
Cheung, L.K.C. (2000): “The Tractarian Operation N and Expressive Completeness” , Synthese, Vol 123, no 2, 247-261
Dugundji, J. (1940). Note on a Property of Matrices for Lewis and Langford's Calculi of Propositions. The Journal of Symbolic Logic, , 5 (4), 150-151.
Dunn, J. M. (1976): "Intuitive Semantics for First-Degree Entailments and Coupled Trees," Philosophical Studies, 29, 149-168.
Dunn, J. M. (2008): "The 4-valued Logic". 2008 International Workshop on Truth Values. Dresden University of Technology.
Feys, R. (1965). Modal Logics. (J. Dopp, Ed.) Collection De Logiique Mathematique ,Serie B.
Fogelin, J.R. (1974): “Negative Elementary Propositions”, Philosophical Studies, 25,189-197.
Fogelin, J. R. (1982): Wittgenstein’s Operator N, Analysis, vol 42, no 3, series 194. 124-127
Font, J. M., & Hájek, P. (2002). On Łukasiewicz's Four-Valued Modal Logic. Studia Logica , 70 (2), 157-182.
Fox, J. (1990): "Motivation and Demotivation of a Four-Valued Logic". Notre Dame Journal of Formal Logic. Volume 31, Number 1, Winter. pp. 76-80.
Geach, P. T. (1981): “Wittgenstein’s Operator N”, Analysis, vol 41, no. 4, series 194, 168-171
Geach, P. T. (1982): “More On Wittgenstein’s Operator N”, Analysis, vol 42, no. 3, series 194, 127-128
Gamut, L. T. F. (1991): (collective pseudonym for: van Benthem, J. F. A. K.; Groenendijk, J. A.G.;de Jongh, D. H. J.; Stokhof, M. J. B.; Verkuyl, H. J.). Logic, Language, and Meaning. Volume 1 Introduction to Logic. University of Chicago Press.
Goodwin, G; James III, C. (2008). Logical Foundations of Four Valued Bit Code. In B. Seinbach (Ed.), Boolean Problems 8th International Workshop, (239-250). Frieberg.
Krolikoski, S. J. (1979). Łucasiewicz's Twin Possibility Functors. Notre Dame Journal of Formal Logic , XX (2), 458-460.
Larner, A. (1979). A Matrix Decision Procedure for Three Modal Logics. Notre Dame Journal of Formal Logic X (3), 599-602
Lemmon, E. J. & Henderson, G. P. (1959). Is there Only One Correct System of Modal Logic. Proceedings of the Aristotelian socaiety/ 33, 23-56. Blackwell Publishing.
Lewis, C. I., & Langford, H. C. (1959). Symbolic Logic (Second ed.). New York: Dover Publications.
Łucasiewicz, J. (1953). A system of Modal Logic. The Journal Of Computing Systems , 1, 111-149.
Moretti, A., (2009), "The Geometry of Standard Deontic Logic". Logica Universalis, online 26 May.
Parry, W. T. (1939). Modalities In The Survey System Of Strict Implication. Journal Of Symbolic Logic , 4 (4), 137-154.
Pavlov, S. (1998): "Sentential Falsehood Logic FL4". Twentieth World Congress of Philosophy. Boston, Massachusetts. August 10-15. Logic and Philosophy of Logic. 1-9.
Pellissier, R., (2008) . ‘“Setting” n-Opposition’. Logica Universalis, 2, 235–263
Purtill, R.L., “Four-Valued Tables and Modal Logic”, Volume XI, Number 4, October 1970, Notre Dame Journal of Symbolic Logic,
Rescher, N. (1965). An Intuitive Interpretation of Systems of Four-Valued Logic. Notre Dame Journal of Formal Logic , VI (2), 155-156.
Rodrigues, O. (1998), Russo, A.: "A Translation Method for Belnap Logic". Imperial College Research Report DoC 98/7. London. 1-17.
Russell, B. (1905 A, October). Necessity and Possibility. Read to the Oxford Philosophical Society.
Russell, B. (1905 B). On Deboting. Mind. 14 (56), 479-493.
Soames, S., (1983): “Generality, Truth Functions, and Expressive Capacity in the Tractatus”, The Philosophical Review XCII, No 4, 573-589
Smessaert, H., (2009), “On the 3D Visualisation of Logical Relations”, Logica Universalis, online 25 July.
Wittgenstein, L. (1961, translated Pears D.F. and McGuinness, B.F.): “Tractatus Logico-Philosophicus”, Routledge, London
