Manila : Bureau of National and Foreign Infermation
Majalah, Jurnal, Buletin
Tubingen : Federal Republic of Germany
Majalah, Jurnal, Buletin
Jakarta : PT Infomed Asih Jaya
Majalah, Jurnal, Buletin
Crawford, Ann Caddell
Charles E. Tuttle, [Date of publication not identified]
Buku Teks SO
Japan : The Hitotsubashi Academy
Majalah, Jurnal, Buletin