1. J. Łukasiewicz, Über den Satz von Widerspruch bei Aristoteles. Bulletin Internationale de l’Académie des Sciences de Cracovie, Classe de Philosophie (1910), 15–38. Also: On the principle of contradiction in Aristotle. In: Review of Metaphysics 24 (1970/71), 485–509
2. J. Łukasiewicz, On three-valued logic (in Polish). Ruch Filozoficzny 5 (1920), 170–171. English translation, in Jan Łukasiewicz. ed. by L. Borkowski (Selected Works. North Holland - Polish Sci. Publishers, Amsterdam-Warsaw, 1970)
3. K. Menger, Statistical metrics. Proc. Natl. Acad. Sci. 28, 535–537 (1942)
4. M. Wajsberg, Axiomatization of the three -valued sentential calculus (in Polish, German summary). C.R. Soc. Sci. Lettr. Varsovie 24, 126–148 (1931)
5. H. Goldberg, H. Leblanc, G. Weaver, A strong completeness theorem for 3-valued logic. Notre Dame J. Formal Logic 15, 325–332 (1974)