Davidosn, D. (1980). Reference service. Bingley.
Lua i Stíl Chicago (17ú heag.)Davidosn, Donald. Reference Service. London: Bingley, 1980.
Lua MLA (9ú heag.)Davidosn, Donald. Reference Service. Bingley, 1980.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.