by Sujono Samba $6.00
by Prof. Soetjipto dan Drs. Raflis Kosasi, M.Sc $9.00
by Prof. Dr. S. Nasution, M.A. $6.00
by Dr. Sofyan Syafri Harahap, M.S,Ac $11.00
by Prof. Dr. Suharsimi Arikunto $11.00
by Moenaf H. Regar $9.00