by M. Najib Azca $6.00
by Dr. C. Asri Budiningsih $7.00
by Dra. L. Simanjuntak $7.00
by Drs. Sidarta Gautama $7.00
by Dr. Ronald Hutapea, SKM, Ph.D $9.00
by Prof. Dr. Suharsimi Arikunto $18.00