- Mail services (e. g., collection, delivery)
- Transportation of mail (e.g., by pony express, rail, air)
- Parcel post
- Special equipment; postal organization and personnel
- Finance (e.g., postal rates, subsidies); etc.
- Express and freight transportation 48, 49, 50
- Postoffice buildings 344
- Postal savings 464
- Government enterprises 655
Outline of Cultural Materials. George P. Murdock, et al., eds. New Haven, Conn. Human Relations Area Files, Inc. 1961. xxv, 164 p.