Books in library catalog: Link
The above list of books was found by searching "Children's Literature" in "Books and Media," and then narrowing by "Era" "19th Century," and "Region" "United States."

Scholarly Peer Reviewed Journals: 

Children's Literature Association Quarterly: Link

Children's literature in education: Link

Children's Literature: Link 

Library Collections Beyond Villanova:

Children's Literature Research Collection at The Free Library of Philadelphia: Link
The Free Library of Philadelphia houses an extensive research collection of children's literature from the 17th century to the present. To make an appointment to view items from our collection, please contact us at   

For additional information on the different components of this collection follow the link above and scroll down on the page. Here you will also find links to digitized parts of the collection that are viewable online. 

Digital Public Library of America: Link
DPLA connects people to the riches held within America’s libraries, archives, museums, and other cultural heritage institutions. All of the materials found through DPLA—photographs, books, maps, news footage, oral histories, personal letters, museum objects, artwork, government documents, and so much more—are free and immediately available in digital format.

New York Public Library Digital Collection: Link
You can search the digital collection for "Children's Literature"