Letter from Stefan Morawski written 27.10.1965

Letter from Stefan Żółkiewski written in 19.03.1968

Letter to the Committee of the Library of Classics of Philosophy written 03.06.1955

Letter to Roman Ingarden written 22.01.1964

Letter to Tadeusz Kotarbiński written 29.05.1953

Letter to Irena Krońska written in 22.08.1963

Letter to Mieczysław Wallis written 29.10.1969