by - $11.00
by Prof. Dr. H.A.R. Tilaar, MSc.Ed $11.00
by Prof. Dr. Sondang P. Siagian, M.P.A $7.00
by Dr. Maryaeni, M.Pd $6.00
by Ny. Susmayati, B.A dan Ny. Hj. Asnidar $6.00
by Prof. DR. Taliziduhu Ndraha $13.00