If you know a veteran’s regiment and the combat division it was attached to, you may find descriptions of the unit's activities.
Some of these specialized records are only available on-site at the appropriate research facility.
Shoulder insignia or patch. Third Division. Military Rootsweb. The white stripes represent the Division's 3 major operations: Marne, St. Mihiel, and Meuse-Argonne
Useful searches include:
Casualty lists, Army Orders, names of divisions, squadrons or units, names of battles, names of people. Look for persons with first names first and the reverse.
Article on 147th aero squadron.