SACK, S. M., & STEINBERG, H. J. (1981). The salesperson's legal guide. Prentice-Hall.
Lua i Stíl Chicago (17ú heag.)SACK, Steven Mitchell, agus Howard Jay STEINBERG. The Salesperson's Legal Guide. New Jersey: Prentice-Hall, 1981.
Lua MLA (9ú heag.)SACK, Steven Mitchell, agus Howard Jay STEINBERG. The Salesperson's Legal Guide. Prentice-Hall, 1981.
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