Division of Commerce of the Department of Agriculture, Industry and Commerce, 1930
Buku Teks SO
Peter H. W. Sitsen
Buku Teks SO
Boeke, J.H.
Institute of pacific relations, 1946
Buku Teks
Pieter Honig, Frans Verdoorn, edited
Board for the Netherlands Indies , 1945
Buku Referensi
Preger W.
F. W. Cheshire pty. ltd. , 1944
Buku Teks SO