Books can be found by searching the following online catalogs:
Dissertations and theses can be found by searching in one of these databases:
Primary sources are the original documents that other scholars write about. For example, for New Testament class papers, a book or letter of the New Testament itself (e.g., 1 Corinthians) would be the primary source
Secondary sources relate to or discuss sources elsewhere. For example, for New Testament class papers, a modern or ancient commentary on 1 Corinthians would be a secondary source discussing the primary source 1 Corinthians.