Columbia subject headings:
Free verse.
Humanism--History--20th century.
Literature and science.
Literature, Modern--20th century--History and criticism.
Literature--Psychology.
Poetry--History and criticism.
Harvard subject headings:
Free verse.
Humanism--History--20th century.
Literature and science
Literature, Modern--20th century--History and criticism
Literature--Psychology
Poetry--History and criticism
Princeton subject headings:
Free verse.
Humanism--History--20th century.
Literature and science.
Literature, Modern--20th century--History and criticism.
Literature--Psychology.
Poetry--History and criticism.