Columbia subject headings:
Germans--Foreign countries--Correspondence.
Heine, Fritz, 1904-2002--Correspondence.
Socialists--Germany--Correspondence.
Sozialdemokratische Partei Deutschlands.
Harvard subject headings:
Germans--Foreign countries--Correspondence.
Heine, Fritz, 1904---Correspondence.
Socialists--Germany--Correspondence.
Sozialdemokratische Partei Deutschlands
Princeton subject headings:
Germans--Foreign countries--Correspondence.
Heine, Fritz, 1904---Correspondence.
Socialists--Germany--Correspondence.
Sozialdemokratische Partei Deutschlands.