Columbia subject headings:
Arx, Cäsar von, 1895-1949--Correspondence.
Authors, Swiss--20th century--Correspondence.
Etter, Philipp, 1891-1977--Correspondence.
Statesmen--Switzerland--Correspondence.
Harvard subject headings:
Arx, Cäsar von, 1895-1949--Correspondence.
Authors, Swiss--20th century--Correspondence
Etter, Philipp, 1891---Correspondence.
Etter, Philipp, 1891-1977--Correspondence.
Statesmen--Switzerland--Correspondence.
Princeton subject headings:
Arx, Cäsar von, 1895-1949--Correspondence.
Authors, Swiss--20th century--Correspondence.
Etter, Philipp, 1891-1977--Correspondence.
Statesmen--Switzerland--Correspondence.