by Drs. A.W. Widjaja $6.00
by ISEI $18.00
by Prof. Dr. Sondang P. Siagian, M.P.A $9.00
by Drs. Ng. Phillips $9.00
by Drs. A. Hasymi Ali $11.00
by $6.00
by Ir. Heinz Frick & Pujo L. Setiawan $7.00