Cita APA (7a ed.)

(1980). Walford's guide to reference material (4th ed.). The Library Association.

Cita Chicago Style (17a ed.)

Walford's Guide to Reference Material. 4th ed. London: The Library Association, 1980.

Cita MLA (9a ed.)

Walford's Guide to Reference Material. 4th ed. The Library Association, 1980.