by Robert K. Yin $7.00
by Prof. Dr. H. Jalaluddin $11.00
by SMP Tjondronegoro, Gunawan Wiradi $25.00
by I Gusti Ngurah Agung $11.00
by Prof. Dr. Suharsimi Arikunto $9.00
by Prof. Dr. Veithzal Rivai $13.00