Primary sources are documents about events and time periods which were written at or around the time they are discussing. They are excellent resources for research as they capture the words, mood, and meaning of the original event or time period. They are excellent to use in research as proof for a statement you are making about an event.
There are archives of primary resources on international relations from countries and agencies all over the world. Many databases of primary source documents are available in digitized forms, either free on the internet or through the Library's databases.
These databases will give you access to online versions of documents, reports and statements from foreign affairs departments and offices in goverments all over the world. Most databases have a searchable index so you can find documents relevant to your research area.