by Prof. Dr. Sondang P. Siagian, M.P.A
$9.00

by Drs. Mulyono HAM, M.Pd
$13.00

by Drs. A. Hasymi Ali
$9.00

by Prof. DR. dr. S.M. Lumbantobing, SpS(K), SpKJ
$6.00

by Katzung
$26.00

by Hudiyanto
$6.00