One way to identify books that are primary sources is to look for books written by people who were involved in the event or activity you are researching. When you look at secondary sources, write down the names of people and then look for them as authors.
In the BGSU Libraries Catalog, the OhioLINK Central Catalog, and WorldCat, books that have been assigned subjects with the subheadings in the list below might be primary sources. However, don’t expect that a book that includes primary sources will always include one of these words or phrases in a subject heading. Also, these subheadings are not used in other databases.
Ambassadors -- United States -- Diaries
Hayes, Rutherford B., 1822-1893 -- Correspondence
Diplomats -- United States -- Biography
Cuban Missile Crisis, 1962 -- Sources
Diplomatic and Consular Services, American -- Thailand -- Biography
For information about the difference between primary and secondary sources, see:
When you know the title of the item you are seeking, the first step is to search by title in an online catalog.