by Drs. Kaelany H.D., M.A $9.00
by Muhaimin $9.00
by Dr. William Hendricks $6.00
by Prof. Dr. Sondang P. Siagian, M.P.A $11.00
by Prof. Dr. Suharsimi Arikunto $13.00
by Prof. Dr. Sukardi, Ph.D $9.00