A dissertation is required of doctoral study; it is a lengthy, formal document that presents new research, and that argues in defense of a particular thesis.
Dissertations can be useful for in-depth research.
Image source: GoogleBooks, Public Domain.
Links below provide access to databases of dissertations.
Some will provide you with citations only (in which case you'll need to use ILL); others will provide you with the full-text.
Request a dissertation via Interlibrary Loan, or Tipasa. Tipasa is a service that will provide you with materials that LVC does not own.
WorldCat Dissertations will provide a Request from LVC Tipasa link on every results record.
You can also request a dissertation from the Interlibrary Loan link on the library's homepage. Note that not all dissertations may be available to borrow.
If we can borrow them, you'll either get a PDF of the dissertation sent to you electronically, or a hard copy that will need to be returned.