by Prof. DR. Taliziduhu Ndraha $12.00
by Prof. Dr. Sondang P. Siagian, M.P.A $7.00
by Maurice Duverger $7.00
by Drs. Husein Umar, S.E., M.M., MBA $13.00
by Djamin, Zulkarnain $5.00
by Drs. Ary H. Gunawan $11.00