The reference for a thesis looks like this:
Author surname, initial. (year). Title of thesis. Type of degree/thesis. University: Country.
For example:
Morris-Adams, M. (2008). Coherence and understanding in informal conversations between native and non-native speakers of English. PhD thesis. Aston University: UK.
These PhD theses by Aston researchers have recently been added to Aston Research Explorer:
American doctoral thesis are available from Ebsco Open Dissertations: EBSCO Open Dissertations Project - Join the Movement (biblioboard.com)