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When you are looking for resources, don't forget books.
Try doing some searches in the Library catalog. If you find some books that are useful to you, go up to that section of the library and browse the area. The library books are shelved by subject, so there will be similar books around the book you found.
Ebook Central is useful, too, because it contains a large number of electronic books.
Dissertations are full-length studies of very specific topics and are book-like in length.