Eagle, Lynne
Taylor & Francis Group, 2015
Buku Teks
Egan, John, 1952-
Sage Publications, 2015
Buku Teks
Egan, John, 1952-
Thomson Learning,, 2007
Buku Teks
Belch, George E.
McGraw-Hill, [date of publication not identified]
Buku Referensi
Clow, Kenneth E.
Pearson, 2016
Buku Teks