1. •Google Books. Previews of many contemporary monographs; increasingly impressive coverage of primary sources (often fulltext)
   

2. •Historical Abstracts. Index of modern journal articles, often with abstracts and/or linked fulltext
   

3. •JSTOR. Fulltext archive of select scholarly journals in history and other fields.
   

4. •Project Muse. Another fulltext archive for a great number of humanities and social-science journals
   

5. •Academic Search Premier. Good for book reviews and some academic articles
   

6. •Eighteenth-Century Collections  Online (ECCO).
   

7. •Nineteenth-Century Masterfile.
   

8. •Chicago Manual of Style. Also see the detailed chapter on formatting notes and bibliography.
   

Also see the key to my editorial remarks and how to mark a book.