Look at the web site Questia before you pay for big buck research esoterica. I have made much use of it for my historicals, with subjects as arcane as Carolingian humor. It does cost some $$ but worth it for research in my opinion. You can browse the subjects before committing $$.
I have actually used Questia for the past four years or so. My recent year-long subscription just expired a week and a half ago. It does help quite a bit. A few years ago they offered a lifetime subscription for something like $300 or $400, but instead I just would do the annual subscription for $100. I wish I did the lifetime subscription when I had the chance, as they have since removed that option.
I will stop subscribing the end of my year because I milked it for all I could. The WWII novel I am working on is too well primary sourced to need Questia. If I go back much farther for another book, I will rejoin.
Perhaps you know about this already, but if you are looking for journal articles online but don't have access through some pay-service (JSTOR, Ebescohost, etc.) you may want to try Google Scholar. If you search for a journal article, they sometimes provide free access to PDF files for download (where it says “PDF from…” on the right side of the page). I have found that Google Scholar is sometimes the best place for me to start looking because it seems to be a very comprehensive journal search engine. If you ever want a search engine which is geared more toward studies on ancient Greek/Roman history, or Italian Renaissance articles and books, let me know and I can provide them to you.
Thank you, I will, if and when. I used to purchase books from The Scholar's Bookshelf, but they went out of business. Many unfortunately were University pubs at excessively high prices. Others are now out of print. Alibris has some bargains though, both nonfiction and fiction. I have used JSTOR for my specific protagonist of the 9th century to great success.