Johannes Hardt and his wife are recorded on the 1798 census of Bangert in Household No. Bg08.
The death of Johann[es] Hardt in 1799 is recorded on the 1811 census of Bangert in Household No. 8.
There are no known surviving male lines of this Hardt family among the Volga German colonies.
- 1811 Bangert Census (Household No. 8).
- 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): Bg08.