Hi Driver Jan and welcome!
Never in here so won't answer from personal experience. Just a few notes.
You should be aware there are people here who still have family in. They won't give too much detail so as to avoid those family in to disconnect from them. So that gives a problem for the research. Also people's experiences while in Scientology are not exactly all roses so they might not want to tell about it too much as it brings back bad memories.
In my signature you can find two lists: a list with names of exes speaking out including lots of videos with people telling their stories, and a list of people who were disconnected from. Maybe that helps.
Also in 2011 someone did a survey amongst people who got out of the cult. It may help:
http://cofsexit.blogspot.nl/2011/01/scientology-exit-survey-results.html
(Could be there are dead links, but just google and go from there.)
I would think the first rule for anyone doing a paper would be to find out what already has been found out.