These databases are useful for finding journal articles on your topic. Some of them (like ProQuest Historical Newspapers and Early American Newspapers) can also lead you to primary sources or historically published material.
These are some useful subject headings for use in the Merlin Catalog.
The links will take you to a list of all of the books in the catalog with that subject heading.
Stowe Harriet Beecher 1811 1896 Uncle Toms Cabin
Stowe, Harriet Beecher, 1811-1896
Stowe Harriet Beecher 1811 1896 Criticism And Interpretation