If you're not sure how to make the most effective use of archives, see this publication from the Society of American Archivists:
WorldCat is the OCLC union catalog, containing over 43 million records describing books and other items owned by libraries worldwide. Each record contains library holdings, including archival materials. There is also a freely available version of WorldCat.
This database is available to BGSU faculty, staff and students, and to walk-in users.
The BGSU Libraries' house rich collections at the Center for Archival Collections.