Columbia subject headings:
Bowen, William, 1836-1893.
Twain, Mark, 1835-1910. Correspondence.
Harvard subject headings:
Bowen, William, 1836-1893.
Twain, Mark, 1835-1910--Correspondence.
Princeton subject headings:
Bowen, William, 1836-1893.
Fiction.
Twain, Mark, 1835-1910. Correspondence.