by Kerry Patterson, Joseph Grenny, Ron McMillan, Al Switzler $12.00
by Soedjono-Dirjosisworo $9.00
by Abdul Mujieb $6.00
by Swasono, Sri-Edi $7.00
by Prof. Dr. Sondang P. Siagian, M.P.A $11.00
by Gunawan Widjaja & Kartini Mulyadi $9.00
by - $7.00
by Clara Ng $6.00
by Grimm Bersaudara $7.00
by Olga Yusuf $7.00
by Prof. DR. dr. S.M. Lumbantobing, SpS(K), SpKJ $6.00
by $11.00