Walford, A. J. (1980). Walford's guide to reference material (4th ed.). The Library Association.
Cita Chicago (17th ed.)Walford, A. J. Walford's Guide to Reference Material. 4th ed. London: The Library Association, 1980.
Cita MLA (9th ed.)Walford, A. J. Walford's Guide to Reference Material. 4th ed. The Library Association, 1980.
Atenció: Aquestes cites poden no estar 100% correctes.