by $12.00
by Drs. Sisdjiatmo Kusumosuwidho, M.Sc $9.00
by Dr. Lijan Poltak Sinambel, M.M., M.Pd., dkk $9.00
by Prof. Abdur Rahman I Do'I, Ph.D $7.00
by Darmadi Durianto, Sugiarto, Lie Joko B. $7.00
by Tinbergen, Jan $6.00