APA
Guffey M. E., . (2004). Business Communication: Process and Product. New York: Thomson South-Western.
Chicago
Guffey Mary Ellen, . 2004. Business Communication: Process and Product. New York: Thomson South-Western.
Harvard
Guffey M. E., . (2004). Business Communication: Process and Product. New York: Thomson South-Western.
MLA
Guffey Mary Ellen, . Business Communication: Process and Product. New York: Thomson South-Western. 2004.