KATZENSTEIN HERBERT. (1992). DIRECT MARKETING (2.). MAXWELL MACMILLAN PUBLICATION LTD.
Lua i Stíl Chicago (17ú heag.)KATZENSTEIN HERBERT. DIRECT MARKETING. 2. NEW YORK: MAXWELL MACMILLAN PUBLICATION LTD, 1992.
Lua MLA (9ú heag.)KATZENSTEIN HERBERT. DIRECT MARKETING. 2. MAXWELL MACMILLAN PUBLICATION LTD, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.