Columbia subject headings:
Literature and society--United States--History--20th century.
Sinclair, Upton, 1878-1968--Criticism and interpretation.
Social problems in literature.
Harvard subject headings:
Literature and society--United States--History--20th century.
Political fiction, American--History and criticism.
Sinclair, Upton, 1878-1968--Criticism and interpretation.
Social problems in literature.
Princeton subject headings:
Literature and society--United States--History--20th century.
Sinclair, Upton, 1878-1968--Criticism and interpretation.
Social problems in literature.