international travels

international travels

Letter to the Polish Academy of Science written 01.07.1963

Letter to the Polish Academy of Science written 04.06.1966

Letter to the Polish Academy of Arts and Sciences written 20.02.1948

Letter to the Polish Academy of Science written 24.10.1963

Letter to the Polish Academy of Science written 10.09.1963

Letter to the Polish Academy of Science written 28.04.1964

Letter to the Polish Academy of Science written 19.10.1963

Letter to the Polish Academy of Science written 05.03.1969