| Subclass U |
Military science (General) |
| Subclass UA |
Armies: Organization, distribution, military situation |
| Subclass UB |
Military administration |
| Subclass UC |
Maintenance and transportation |
| Subclass UD |
Infantry |
| Subclass UE |
Cavalry. Armor |
| Subclass UF |
Artillery |
| Subclass UG |
Military engineering. Air forces |
| Subclass UH |
Other services |
https://www.loc.gov/aba/cataloging/classification/lcco/lcco_u.pdf