(1980). Walford's guide to reference material (4th ed.). The Library Association.
Citazione stile Chigago Style (17a edizione)Walford's Guide to Reference Material. 4th ed. London: The Library Association, 1980.
Citatione MLA (9a ed.)Walford's Guide to Reference Material. 4th ed. The Library Association, 1980.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.