by Drs. Domi C. Matutina $12.00
by Eddy Tano, Dipl. Chem. Eng. $9.00
by Mulyadi Subri $9.00
by Drs. Inu Kencana Syafiie, Djamaludin Tandjung, dan Supardan Modeong $11.00
by Drs. Muda Markus $20.00
by Zulkarimein Nasution $9.00