Columbia subject headings:
English poetry--19th century--History and criticism.
English poetry--20th century--History and criticism.
Yeats, W. B. (William Butler), 1865-1939--Criticism and interpretation.
Harvard subject headings:
English poetry--19th century--History and criticism
English poetry--20th century--History and criticism
Yeats, W. B. (William Butler), 1865-1939--Criticism and interpretation.
Princeton subject headings: