Kotler, Philip, author
Holt, Rinehart and Winston , 1971
Buku Teks
Walker, Orville C., author
McGraw-Hill, 2006
Buku Teks
Howard, John A., author
Richard D. Irwin, 1957
Buku Teks
Taylor, Weldon Johnson, 1908-, author
South-Western Publishing, 1975
Buku Teks
Duddy, Edward, author
Mcgraw-Hill, 1953
Buku Teks