by Eddy Tano, Dipl. Chem. Eng. $9.00
by Prof. Mr. Roeslan Saleh $6.00
by Drs. S. Margono $9.00
by Drs. H. Abu Ahmadi $9.00
by Prof. Mr. Notonagoro $9.00
by Prof. Dr. S. Nasution, M.A. $7.00