by Prof. Dr. Sondang P. Siagian, M.P.A $7.00
by Drs. Muchdarsyah Sinungan $9.00
by Radiks Purba $12.00
by Ir. Suharto $7.00
by Drs. Ahmad Rohani., H.M., M.Pd $6.00
by T.F. Honour dan R.M. Mainwaring $11.00