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

by Sudarto
$6.00

by Drs. Harjanto
$9.00

by Prof. Dr. Suharsimi Arikunto
$6.00

by Drs. Abdullah Ali, Drs. Misbandono, dan Ir. Eny Rahma
$7.00

by FMIPA Universitas Indonesia
$6.00