Columbia subject headings:
Authors, German--19th century--Correspondence.
Authors, German--20th century--Correspondence.
Authors, Swiss--19th century--Correspondence.
Heyse, Paul, 1830-1914--Correspondence.
Keller, Gottfried, 1819-1890--Correspondence.
Harvard subject headings:
Authors, German--19th century--Correspondence
Authors, German--20th century--Correspondence
Authors, Swiss--19th century--Correspondence.
Heyse, Paul, 1830-1914--Correspondence.
Keller, Gottfried, 1819-1890--Correspondence.
Princeton subject headings:
Authors, German--19th century--Correspondence.
Authors, Swiss--19th century--Correspondence.
Heyse, Paul, 1830-1914--Correspondence.
Keller, Gottfried, 1819-1890--Correspondence.