Hotchkiss, George Burton, author
Macmillan, 1950
Buku Teks
Drewniany, Bonnie L., author
Wadsworth, Cengage Learning, 2014
Buku Teks
Clarke, George Timothy
New York University, 1959
Buku Teks
Lewis, Herschell Gordon, author
Prentice-Hall, 1988
Buku Teks
edited by George Zinkhan
American Marketing Association, 2000
Buku Teks