For further research you may want to browse the following call number ranges.
D501 - D680 World War I.
D529 - D578 Campaigns.
D580 - D589 Naval Operations.
D114. Center of Military History
D221. Naval Historical Center
W85.1 - W85.5 Training Camp Activities Commission
W87.1 - W87.27 Air Service
W90.1 - 90.4 Tank Corps
W88.1 - W88.4 Motortransport Corps
W95.1 - W95.25 American Expeditionary Forces
Wt1. - Wt5. Wartrade Board
For a subject search, look under European War, 1914-1918 as well as World War, 1914-1919.