Norton, H. R. (1919). A textbook on retail selling. Ginn and Company.
Lua i Stíl Chicago (17ú heag.)Norton, Helen Rich. A Textbook on Retail Selling. Boston : New York [etc.]: Ginn and Company, 1919.
Lua MLA (8ú heag.)Norton, Helen Rich. A Textbook on Retail Selling. Ginn and Company, 1919.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.