by Eddy Tano, Dipl. Chem. Eng. $9.00
by Prof. DR. S.P. Siagian, M.P.A $9.00
by Drs. Syaiful Bahri Djamarah $7.00
by Collin Mclver $9.00
by I. Al-Abyadi, Terj. Halimuddin, S.H $7.00
by Victor Situmorang, S.H $7.00