by Drs. Daryanto $6.00
by Syahrin Harahap $9.00
by FMIPA Universitas Indonesia $6.00
by Tobi Moektijono $6.00
by Drs. Abdullah Ali, Drs. Misbandono, dan Ir. Eny Rahma $7.00
by Prof. Dr. Oemar Hamalik $7.00