by $7.00
by WK $13.00
by Bayu Adjie $9.00
by Ir. L. Widarto & FX. Sudarto C. Ph $5.00
by Drs. Ec. Alex. S. Nitisemito dan Drs. M. Umar Burham. M.S $6.00
by Ir. Abbas Siregar Djarijah $5.00