Robinson, O. P., Blacker, W. R., & Logan, W. B. (1966). Salesmanship. Prentice-Hall.
Lua i Stíl Chicago (17ú heag.)Robinson, O. Preston, William R. Blacker, agus William B. Logan. Salesmanship. Englewood Cliffs, New Jersey: Prentice-Hall, 1966.
Lua MLA (9ú heag.)Robinson, O. Preston, et al. Salesmanship. Prentice-Hall, 1966.
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