Your best bet for finding scholarly sources on your topic is the Library Catalog (Books link on the library's homepage). You don't have to read the whole book! Often, you just need a chapter or section that addresses your topic. If you can come to campus, there are many books in the general collection. If you can't come to campus, there are many e-books available as well.
Try this keyword search: [your topic] AND early church
To find journal articles, you can try searching within one relevant journal such as:
OR you can search your topic in article databases by using the EBSCO Quick Search, which includes the Philosopher's Index and other relevant academic databases. Click on Peer Reviewed to limit to scholarly articles.
Here are some examples of scholarly e-books about the early church that might be helpful. Use the Library Catalog (see instructions above) to search for other topics.