Cain, Brian, author
Glorier International, 1999
Buku Referensi
Griffin, Ricky W., author
Prentice-Hall, 2002
Buku Teks
Griffin, Ricky W., author
Prentice-Hall, 2002
Buku Teks
Griffin, Ricky W., author
Pearson, 2015
Buku Teks
edited by Victor Lazzaro
Prentice-Hall, 1968
Buku Referensi