by Dr. Ronald Hutapea, SKM, Ph.D $9.00
by Drs. Sudarso $6.00
by Supardan $7.00
by Prof. Padmo Wahyono, S.H $13.00
by Drs. H. Abdul Fatah $7.00
by Eddy Tano, Dipl. Chem. Eng. $7.00