1. Stanislaw Leśniewski, Grundzüge tints neven Systems der Grundlagen der Mathematik (Reprinted from Fundamenta Mathematics 14 (Warsaw, 1929). pp. 13 ff.. 67 ff
2. Edmund Husserl, Logische Untersuchungen, vol. ii. part I (2nd rev. ed. Halk/S. 1913). pp. 294,295.305–12.316–21.326–42.
3. R. Carnap, Abriss der Logistik (Vienna 1929). p. 30: A. Tarski, Projecie prawdy w językach nauk dedukeyjnych (The Concept of Truth in Formalized Deductive Sciences) (Warsaw 1933 ). p. 67.
4. 1. Cf Jan Łukasiewiez, 'Philosophische Bemerkungen zu mehrwertigen Systemen des Aussagenkalküls'. Comptes rendus des séances de la Société des Sciences et des Lettres de Varsovie 13. CI. iii (Warsaw 1930). ['Philosophical Remarkson Many-Valued Systems of Piopositional Logic'. Jan Łukasiewiez 2. Selected Works, ed. by L Borkowski. North- Holland, 1970, pp. 153-178.]
5. Selected Works, ed. by L Borkowski. North- Holland, 1970, pp. 153-178.]