by Helbert A. Simon $13.00
by M. Firdaus $0.00
by Drs. Robinson Tarigan, M.R.P $11.00
by Ir. Moehar Daniel, M.S & Ir. Darmawati, M.Sc & Ir. Nieldalina, M.Si $7.00
by Aziz Alimul $9.00
by Dripa Sjabana $7.00