Nickels, W. G. (1987). Understanding Business / William G. Nickels. St. Louis.
Lua i Stíl Chicago (17ú heag.)Nickels, William G. Understanding Business / William G. Nickels. St. Louis, 1987.
Lua MLA (8ú heag.)Nickels, William G. Understanding Business / William G. Nickels. St. Louis, 1987.
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