by Patt Roesle Materka $9.00
by Ir. Moehar Daniel, M.S & Ir. Darmawati, M.Sc & Ir. Nieldalina, M.Si $7.00
by Drs. Muchdarsyah Sinungan $11.00
by Ir. Budi Rafitas $7.00
by Dr. Moh. Efendi, M.Pd., M.Kes $7.00
by Prof. Dr. S. Nasution, M.A. $6.00