by Prof. Dr. S. Nasution, M.A.
$7.00

by Ir. Rustam Hakim, M.T., IALI & Dr. Ing. Ir. Eka SediadiR., IAI
$9.00

by Dr. Ir. Hermawan Thaheer
$11.00

by Fausiah, Fitri, & Julianti Widury
$7.00

by Mansur Samin
$6.00

by Donald J. Bawersok
$12.00