Hopkins, T. (1982). How to master the art of selling. Warner Books.
Lua i Stíl Chicago (17ú heag.)Hopkins, Tom. How to Master the Art of Selling. New York: Warner Books, 1982.
Lua MLA (9ú heag.)Hopkins, Tom. How to Master the Art of Selling. Warner Books, 1982.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.