Bolling, C. (1930). Retail Salesmanship (2nd.). Isaman Pitman.
Lua i Stíl Chicago (17ú heag.)Bolling, C. Retail Salesmanship. 2nd. London: Isaman Pitman, 1930.
Lua MLA (9ú heag.)Bolling, C. Retail Salesmanship. 2nd. Isaman Pitman, 1930.
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