You can use the catalog to search for primary sources contained within articles and books.
Primary documents may be contained in biographies or other books on specific movements or events, such as civil rights. Search the catalog using the terms speech*, correspondence, letter*, or documents, in addition to your topic of interest.
Also, you can filter your article and book searches by date, and find primary sources from the time period you are focusing on.
You can also do an author search if there are prominent individuals related to your topic and look for articles and books authored by those individuals.
Try searching JSTOR for primary sources. You'll want to do an advanced search and limit by date range for the time period you're focusing on.
The New York Times creates country profiles with a chronology of news stories and sometimes links to other sources. This can give you a good overview of current affairs in that country. Here's an example on Kenya. To find profiles, do a search on the name of the country.
Full text articles from the NYT are only available online back to 1980 in the Nexis Uni database.
To find older articles, go to the NYT website and click on "Search" on the top left side of the page. On the results page you can click the "All Results Since 1851" link and then sort by "Oldest" to get to older article citations. Or, you can click on "specific dates" to enter a specific date range. Most older articles at the NYT website are not freely available full text. Unless you have a NYT subscription, you can only access articles before 1923 or after 1980 and you are limited to viewing 10 NYT articles a month. However, the library owns microfilm of issues from 1923-2005 which can be viewed and printed on the first floor of the library.