Correspondence of the General Secretariat with the members of the Bureau (1960): Charles E. Odegaard, Ronald Syme, Silvio Zavala, Felice Battaglia, Jules Marouzeau, Hans R. Hahnloser, R.N. Dandekar; general correspondence
General Secretariat: correspondence (1961-early 1962); correspondence with board members: Charles E. Odegaard, Ronald Syme, Silvio Zavala, Felice Battaglia, Jules Marouzeau, Hans R. Hahnloser, R.N. Dandekar, Kazimir Kumaniecki
General Secretariat: correspondence with members of the Bureau (1964): Charles E. Odegaard, Ronald Syme, Silvio Zavala, Hans R. Hahnloser, Tetsuro Yamamoto, Kazimir Kumaniecki, C.C. Berg, Jean d'Ormesson; general correspondence
General Secretariat: correspondence with the members of the Bureau (1969): Ronald Syme, Silvio Zavala, Hans R. Hahnloser, C.C. Berg, Jean d'Ormesson, Jaroslav Prusek, Rensselaer W. Lee, Ali Akbar Siassi
General Secretariat: correspondence with the members of the Bureau (1970): Ronald Syme, Silvio Zavala, Hans R. Hahnloser, Jean d'Ormesson, Jaroslav Prusek, Ferdinand N'Sougou Agblemagnon