by Michael P. Todaro $12.00
by Leech, Geoffrey $7.00
by Dra. Zuhairini, dkk $9.00
by - $9.00
by Drs. Robinson Tarigan, M.R.P $11.00
by Drs. R. Suharno $6.00
by Prof. Dr. S. Nasution, M.A. $6.00