Indonesia in the 1990's
Euromoney Publication, 1991
 Buku Teks
An Outline of Japanese taxes 1990
Printing Bureau, Ministry of Finance , 1990
 Buku Teks
Britannica book of the year 1990
Encyclopaedia Britannica Inc., 1990
 Buku Referensi
International Petroleum encyclopedia 1990
editor, John C. McCaslin
PennWell Publishing , 1990
 Buku Referensi
The World competitiveness report 1990
The World Economic Forum, 1990
 Buku Teks