| Arbeitsgemeinschaft USA CANADA | ArGe USA CANADA |
| Bund Deutscher Philatelisten e.V. | BdPh |
| Forum des Bundes Deutscher Philatelisten | BdPh Forum |
| American Philatelic Society | APS |
| Philatelistische Bibliothek Hamburg | Philatelistische Bibliothek Hamburg |
| Linn's Stamp News und Scott Katalog | Linn's |
| Philatelistic Foundation | Philatelistic Foundation |
| The Canal Zone Study Group | CZSG |
| TPO & Seapost Society - German Sea Post Offices on German and American Ships | TPO & Seapost Society |
| The digitized "Postal Bulletins" and "Postal Laws & Regulations" of the USA | US POSTAL BULLETINS and PL & Rs |
| "Statue of Liberty" and "Ellis Island" - Archive about travelers arriving by ship (Also US citizens) | The Statue of Liberty - Ellis Island Foundation, Inc. |
| National Archives | National Archives |
| Example: National Archives - Post Office Records | National Archives - Post Office Records |
| Europeana - Network of many European libraries (also the one in Hamburg) - here the newspapers (English site) | Europeana - Newspapers |