Nikolaus Denk and his family are recorded on the 1798 census of Bettinger in Household No. Bt12.
The death of Nikolaus Denk in 1821 is recorded on the 1834 census of Bettinger in Household No. 36.
- 1834 Bettinger Census (Household No. 36).
- Mai, Brent Alan. 1798 Census of the German Colonies along the Volga: Economy, Population, and Agriculture (Lincoln, NE: American Historical Society of Germans from Russia, 1999): Bt12.