| Call Number | Subject |
|---|---|
| D 1-24.5 | General |
| Call Number | Subject |
|---|---|
| HE 5880-5990 | Express service Including commercial package delivery services See also HF5761+ Shipping of merchandise, etc. |
| - HE 5893-5990 | - By region or country |
| - - HE 5893-5904 | - - United States |
| - - - HE 5903.A-Z | - - - Individual companies, A-Z |
| - - - - HE 5903.A55 | - - - - American Express |
| - - - - HE 5903.F43 | - - - - Federal Express |
| - - - - HE 5903.U54 | - - - - United Parcel Service (UPS) |
| - - - - HE 5903.W5 | - - - - Wells Fargo |
| HE 5999 | Freight forwarders. Mail receiving & forwarding services |
| Call Number | Subject |
|---|---|
| HE 6011 | Congresses |
| HE 6071 | General works |
| HE 6101-6241 | Special topics |
| - HE 6125-6148 | - Rates |
| - HE 6182-6228 | - Stamps. Postmarks |
| - - HE 6182-6183 | - - History & description |
| - - - HE 6182 | - - - General works |
| - - - HE 6183.A-Z | - - - Postage stamps. Postmarks. By topic, A-Z |
| - - - HE 6184.A-Z | - - - Other aspects of postage stamps, A-Z |
| - - - - HE 6184.C65 | - - - - Covers |
| - - - - HE 6184.D4 | - - - - Design |
| - - - - HE 6184.F57 | - - - - First day covers |
| - - - - HE 6184.R3 | - - - - Rare stamps |
| - - HE 6185.A-Z | - - By region or country, A-Z |
| - - HE 6187-6228 | - - Stamp collecting. Philately |
| - - - HE 6215 | - - - Handbooks, manuals, etc. |
| - - - HE 6224-6228 | - - - Catalogs. Price lists. Exchange lists |
| - HE 6239.A-Z | - Other special topics, A-Z |
| - - HE 6239.E54 | - - Electronic mail systems see HE7551 |
| HE 6246-6278 | International postal service |
| HE 6300-7496 | By region or country |
| - HE 6300-6500 | - United States |
| - - HE 6361-6368 | - - Guides. Directories |
| - - HE 6371-6376 | - - History Including general works on the United States Postal Service |
| - - - HE 6371 | - - - General works |
| - - - HE 6375.A-Z | - - - Special topics, A-Z |
| - - - HE 6376 | - - - Local |
| - - HE 6401-6497 | - - Special |
| - - - HE 6425-6448 | - - - Rates |
| - - - HE 6477 | - - - Mail steamers. Steam packet. Ocean mail stamps |
| - - - HE 6496 | - - - Air mail service |
| - - HE 6499 | - - Civil service. Postal service employees. Letter carriers Including selection, salaries, etc. |
| - HE 6651-7496 | - Other regions or countries |
| - - HE 6651-6660 | - - Canada |
| - - HE 6921-7180.8 | - - Europe |
| - - - HE 6931-6960.5 | - - - Great Britain |
| Call Number | Subject |
|---|---|
| HE 7511-7549 | Pneumatic service See also TJ1015 Mechanical engineering |
| HE 7551-7553 | Electronic mail systems See also TK5105.73+ Local area networks |
| - HE 7551 | - General works |
| - HE 7553 | - Spam For filtering of spam in local area networks see TK5105.743 |