. . "21st Reserve Division (German Empire)" . . . . . "21st" . . "21st Reserve Division (German Empire)" . "Imperial German 21st Reserve Division" . "21st Reserve Division" . . "Approx. 15,000" . . . . . . "Reserve Field Artillery Regiment No. 21" . . . . . . . "1914" . . . . . . . . "1919" .