by Drs. Agus M. Hardjana, M.Sc., Ed $6.00
by Adnan Buyung Naution $40.00
by Prof. Dr. J. Winardi, SE $9.00
by Fakultas Psikologi Untar $6.00
by Oren Harari $11.00
by Hiroyosi Kano $10.00
by Katzung $24.00