When you start working on your dissertation, the first thing you need to take care of is dissertation data. Dissertation data is not like the sources you used to write a school research paper. You will need much more than just five or seven of them.
 
Do not panic once you get the requirements for the number of sources needed to complete a dissertation. Actually, dissertations data can be received from many places. We will list only a few of them. The rest is up to your understanding of the concrete problem.

1. If you are talking about proper dissertation analysis and reliable dissertation data, you are talking about authentic texts. We can demonstrate it by telling you that reading the original Hamlet text will be much more helpful and professional than reading tons of critical literature as dissertation data.
2. But do not reject critical works at all. They are still useful dissertations data. You just need to know how to use them right. First of all, not all the critical works are good for dissertation data. Choose acknowledged ones. Do not cite them everywhere. Better process them and come up with your own conclusions, give your own answers, and this will make your research correspond to the used dissertation data.
3. When writing a dissertation, use specialized journals as dissertations data. If you are lucky to find more than one useful article in a certain journal, you end up with more sources to put on your list of references, for they count as separate ones in dissertation data.

4. Finally, there are encyclopedias, both in stationary and virtual libraries. With proper citing, you can and should use them as dissertations data. Certainly, this kind of dissertation data is somewhat peculiar, but it still counts.