by Evelyn Clark $9.00
by Dr. Ir. H. Suprijanto $9.00
by Prof. Dr. S. Nasution, M.A. $6.00
by Prof. Dr. Husaini Usman, M.Pd., M.T $16.00
by Drs. P. Sumardji $6.00
by Adrian Perkasa $4.32