The library catalog can also be used to locate primary sources, from the library's homepage (lib.msu.edu), go up to Find & Borrow, then choose Books & Media. Click on Advanced. Along with another keyword specific to your topic, use one of the following subject terms, changing from All Fields to Subject:
The library has many other primary source databases, which I encourage you to look through: A-Z List of Primary Source Databases
Use the Subject drop-down menu to find collections related to your topic.
You can get to the Database list from the library's homepage by following these directions: