by Ir. Rabiatual Adawyah, M.P $7.00
by Guenther, Ernest $7.00
by F. A. Suwandi Wihardjo, B. Sc $6.00
by Prof. Dr. Soekartawi $7.00
by Dogra, S.K & S. Dogra $12.00
by Suryokusumo, Sumaryo $6.00