The first requirement for a dissertation submitted in candidature for the degree is that it presents the results of the candidate's own work. Clearly, this demand does not exclude quotations or the representation of the views or results of other scholars in the field. Indeed, another expectation in any dissertation is that the candidate will relate his or her own work to that of other researchers.
What is of the first importance is that in writing your dissertation you must clearly and unambiguously distinguish between your own thoughts, conclusions and results and those of other scholars. The standard mechanism for ensuring that a plain distinction is made is by means of quotation marks, for direct quotations from the work of other scholars, and references to acknowledge indirect use of the work of other scholars. References must be sufficiently precise to enable the reader to obtain and consider the original work.
The aim of a reference is to enable the reader to locate and consult the work you have cited in your dissertation.
References are used to indicate the works mentioned in the text but the bibliography, placed at the end of the dissertation (before the index), will not only provide the necessary details of cited work but also other works that have been useful in your study, even if they are not explicitly cited in the text.