Götzen's work provided a basis for a more comprehensive exercise by J.J. Polak, a Dutch economist at Princeton University, who was commissioned by the Dutch East Indies government in exile during 1942-43 to estimate Indonesia's national income. Polak (1943) had to make do with sources available in the United States.He used income tax data to estimate total income for the European and 'Foreign Asiatic' groups, and output and wage data by industrial sector to approximate total income of indigenous Indonesians for 1921-39. Polak's work was not immediately published upon completion, largely because it showed that average income in the group of Europeans was 50 times higher than average income among indigenous Indonesians, which 'did not satisfy the publicity aspirations of those who had commissioned [the report]' (letter by J.J. Polak to the author, 13 May 1996). After an abstract in Dutch was published in 1947 and the University of Indonesia had mimeographed copies in 1950s, the work was finally published in full in 1979.