Jacobsen, Charles W.; Willett, James F.; Anderson, Delmer P.; Sachs, Edward I.; Smith, Hiram C.; Walsh, James E.; Forwood, William G.; Purcell, William W. R.
"The extraordinary importance which the Gruson-Schumann Shielded Mountings have obtained in military science during the last five years has naturally somewhat diverted the public interest from the armoured turrets and batteries of the Gruson...
This manual is intended to prescribe the duties to be performed by the personnel manning antiaircraft machine guns, and to explain the mechanical action of the gun and the workings of related materiel so that antiaircraft machine-gun equipment.