Gaya APA
Posner, J, M, K, D, B, Z.
(1999).
The Leadership Challenge
(
1)
.
Batam:
Interaksara.
Gaya MLA
Posner, James, M., Kouzes, Dan, Barry, Z..
"The Leadership Challenge".
1
Batam:
Interaksara,
1999.
Text.