Daniel Appel and his wife are recorded on the 1798 census of Straub in Household No. Sr04.
There are no known surviving male lines of this Daniel Appel among the Volga German colonies.
[There is a Michael Appel, a farmer, his wife Anna Margaretha, and sons (Johann Lorenz, age 17; Daniel, age 15) who arrived from Lübeck at the port of Oranienbaum on 29 August 1766 aboard the ship Apollo under the command of Skipper Detlov Merberg. The Oranienbaum passenger list records that this Michael Appel came from the German region of Isenburg.]
- 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): Sr04.
- Pleve, Igor. Lists of Colonists to Russia in 1766: Reports by Ivan Kulberg (Saratov: Saratov State Technical University, 2010): #5162.