by Eddy Tano, Dipl. Chem. Eng. $7.00
by Thompson Ngoen $12.00
by Ir. L. Widarto & FX. Sudarto C. Ph $5.00
by M. Gani Kristianto $12.00
by Aziz Alimul $11.00
by Budi Streptiadi $7.00