by Prof. Dr. Sondang P. Siagian, M.P.A $11.00
by Lyle W. Morgan II, Ph.D., HMD $7.00
by Nursalam $12.00
by dr. Iwan Ikayuda, dr. Sukonto K., Prof. dr. Sjahriar R $20.00
by Brooks $20.00
by Syam Hardy $7.00