Kotter, John P., 1947-, author
Free Press, 1997
Buku Teks
Perkins, Dennis N.T., 1953-, author
Amacom, 2012
Buku Teks
Perkins, Dennis, author
Amacom, 2012
Buku Teks
Bosworth, A.B., author
Cambridge University Press, 1995
Buku Teks
Hughes, Richard L., author
McGraw-Hill, 2012
Buku Teks