by Prof. Dr. Sondang P. Siagian, M.P.A $9.00
by Anwar, Moh. Arsjad, dkk $9.00
by Arthur F. Carmazzi & David M. Rogers $7.00
by Gerry Spence $13.00
by Gavin Keunedy $11.00
by Istimawan Dipohusodo $18.00