by Ir. Abbas Siregar Djarijah $6.00
by Ir. Daisy P. Sriyadi Hendaryono $6.00
by $7.00
by Prof. J. Suprapto, M.A. APU $11.00
by Drs. H. Malayu S.P. Hasibuan $11.00
by J. Price Gittinger $6.00