Citazione Stile APA (7a Edizione)

(1987). Walford's guide to reference material (4th ed.). Library Association.

Citazione stile Chigago Style (17a edizione)

Walford's Guide to Reference Material. 4th ed. London: Library Association, 1987.

Citatione MLA (9a ed.)

Walford's Guide to Reference Material. 4th ed. Library Association, 1987.