1. Kotarbinski, Tadeusz 1920. ‘Sprawa istnienia przedmiotow idealnych’. PF, (š 1.0) vol. 28, as reprinted in 1958, pp. 7–39. (Question of existence of ideal objects. Contains summary of Lesniewski's arguments and views.)
2. Kotarbinski, Tadeusz 1929. Elementy Teorji Poznania, Logiki Formalnej i Metodologji Nauk. Lwow. (Elements of theory of knowledge, formal logic, and methodology of science. Preface acknowledges Lesniewski's pervasive influence. Characterization of Lesniewski's ontology in pt. 3, ch. 3, contains illustrative theses of elementary ontology, and was for more than two decades the only elementary published account. Ed. 2, revised, 1961, Warsaw.)
3. Kotarbinski, Tadeusz 1957. Wyklady z Dziejow Logiki. Lodz. (Lectures from history of logic. Contains personal recollections of Lesniewski's unpublished treatments of certain topics in semantics, together with brief informal accounts of his theories.)
4. Kotarbinski, Tadeusz 1958. Wybor Pism, vol. 2. Warsaw. (Selected writings.) Lejewski
5. ‘Logic and existence’;Czeslaw;British Journal for the Philosophy of Science,1954