Poole, Jon, author
Financial World, 2011
Buku Teks
Ponder, Randall D., author
EP Entrepreneur Press, 2005
Buku Teks
Maxwell, John C., author
NY : Center Street, 2014
Buku Teks
Burns, James McGregor, author
Harper and Row, 1978
Buku Teks
Maxwell, John C., author
Menuju Insan Cemerlang, 2016
Buku Teks