Walters, C. Glenn, author
South Western Publishing, 1989
Buku Teks
Schiffman, Leon G., author
Pearson Education, Inc., 2007
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Asseal, Henry
Kent Publishing Company, 1984
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Anya Safira, author
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2013
UI - Skripsi (Membership)
Engel, James F., author
Chicago Dryden Press, 1990
Buku Teks