Letter from Kazimierz Ajdukiewicz written 6/19/1948

Postcard from Maria Turowicz written 14.11.1966

Letter to Władysław Tatarkiewicz written 20.01.1961

Letter from Tadeusz Czeżowski written 8/1/1948

Letter from Stefan Żółkiewski written in n.d.

Letter to Władysław Tatarkiewicz written 20.03.1967

Letter to the Committee of the Library of Classics of Philosophy written 29.01.1953

Letter to the National Scientific Publishers written 30.03.1963

Letter to the Polish Academy of Science written 28.04.1964

Letter to Adam Schaff written 30.08.1968

Letter from Stefan Błachowski written 13.07.1945

Letter to Anna Teresa Tymieniecka written 21.03.1969