1. Bochenski I. M. (1970) A history of formal logic. Chelsea Publishing Co, New York
2. Boh I. (1993) Epistemic logic in the later Middle Ages. Routledge, London
3. Bolzano, B. (1837). Wissenschaftslehre (Vols. I–IV). J. von Seidel, Sulzbach. Cited as WL.
4. Brentano F. (1930) Wahrheit und Evidenz, cited after the second edition. Felix Meiner, Hamburg
5. Carnap R. (1937) The logical syntax of language. Routledge and Kegan Paul, London