Isaak Dubois, a teacher of French (Schulmeister der französischen Sprache), his wife Johanna Gertrude, and children (Ernst Friedrich, age 17; Helena, age 7) are recorded on the 1767 census of Katharinenstadt in Household No. 26. They had settled there on 27 August 1766.
The 1767 census records that Isaak Dubois is from the German town of Berlin in Brandenburg, and Johanna Gertrude is from the German town of Schönebeck in the Magdeburg region.
- 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): Ka031.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 2 (Göttingen: Göttinger Arbeitskreis, 2001): 282.