Nelson, R. (2009). The greatest sales training in the world. Jaico Publishing House.
Lua i Stíl Chicago (17ú heag.)Nelson, Robert. The Greatest Sales Training in the World. Ahmedabad: Jaico Publishing House, 2009.
Lua MLA (9ú heag.)Nelson, Robert. The Greatest Sales Training in the World. Jaico Publishing House, 2009.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.