Columbia subject headings:
Gershwin, George, 1898-1937. Porgy and Bess--Criticism and interpretation.
Musical theater--United States--History and criticism--20th century.
Harvard subject headings:
Gershwin, George, 1898-1937. Porgy and Bess
Gershwin, George, 1898-1937. Porgy and Bess--Criticism and interpretation.
Musical theater--United States--History and criticism--20th century.
Princeton subject headings:
Gershwin, George, 1898-1937. Porgy and Bess.