Lucas, R. W. (2009). Customer Service (4th.). McGraw Hill.
Lua i Stíl Chicago (17ú heag.)Lucas, Robert W. Customer Service. 4th. New York: McGraw Hill, 2009.
Lua MLA (9ú heag.)Lucas, Robert W. Customer Service. 4th. McGraw Hill, 2009.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.