Judul asli : "The Essence of Leadership"
Bibliografi : hlm. 199-201
No Inv.: 132176/SM/Perp/12/1c~135722/SM/Perp/13/1c
Bibliografi : hlm. 218
No Inv.: 156/S/99/1c
Termasuk bibliografi No Inv.: 139747, 139748/P/Perp/14/2c
No. Inv. : 150344-150345/P/Perp/15/2c