Cita APA (7th ed.)

Downs, R. B. (1951). American library resources: A bibliographical guide. American Library Association.

Cita Chicago (17th ed.)

Downs, Robert Bingham. American Library Resources: A Bibliographical Guide. Chicago: American Library Association, 1951.

Cita MLA (9th ed.)

Downs, Robert Bingham. American Library Resources: A Bibliographical Guide. American Library Association, 1951.