by Drs. G. Kartasapoetra $7.00
by Ir. Hatta Sunanta, B.Sc., MS $6.00
by Ir. Heinz Frick & Pujo L. Setiawan $7.00
by H. Rahmat Rukmana $6.00
by Hiro Tugiman $11.00
by Rondang Pasaribu $6.00