by Dr. Ronald Hutapea, SKM, Ph.D $6.00
by Susmayati, B.A., dkk $7.00
by Claude P. Wratal $13.00
by Drs. Agus M. Hardjana, M.Sc., Ed $6.00
by Mulyadi Subri $9.00
by Leo Suryadinata $4.61