Columbia subject headings:
Germany--History--1789-1900.
Germany--History--20th century.
Kaehler, Siegfried A. (Siegfried August), 1885-1963.
Harvard subject headings:
Germany--History--1789-1900.
Germany--History--20th century.
Kaehler, Siegfried A. (Siegfried August), 1885-1963.
Princeton subject headings:
Germany--History--1789-1900.
Germany--History--20th century.
Kaehler, Siegfried A. (Siegfried August), 1885-1963.