I recommend Christopher's answer (above). I used the software entitled Reference Manager but (have just had a quick look), I don't think it is still available although I could not be certain. But with a lot to reference, it helped me when I needed to be accurate and time was finite.
I have just looked up EndNote, which looks comparable.
But if you are doing a smaller piece of work, you could do it manually.
What style of referencing are you using? I have just checked, and you can look on the Internet about how to reference a dissertation in the style that you are using - for example - Harvard. If the dissertation has been published, you could look it up on Google Scholar, then click on the 2 apostrophes '' in blue below the info about the dissertation and bring up a selection of versions of referencing styles.