by Sugiarto, Dergibson Siagian, dkk $7.00
by John M. Echols & Hasan Shadily $18.00
by J. Donald Walters $9.00
by Arleen Amijaya $6.00
by Drs. Husein Umar, S.E., M.M., MBA $9.00
by John Gottman, Ph.D. $9.00