by Jack Trout dan Steven Rivkin $6.00
by P. A. Elliot $9.00
by Prof. J. Suprapto, M.A. APU $11.00
by Prof. Dr. S. Nasution, M.A. $7.00
by Dr. Ismail Abdul Mutalib Al-Khatib $5.00
by Richard Denny $7.00