Handbook for plantation in Deli, East Sumatra contains rules governing the employment contract.
Laporan tahunan manajemen A. V. R. O. S. periode 1 Januari hingga 31 Desember 1940.
An introduction to plant tobacco in terms of agronomy, engineering, and chemistry.
Housing conditions for farm workers in eastern Sumatra to 1952.
Laporan dari Sekolah Asosiasi Pekebun di Brastagi