Browse all the East Germany-related books and ebooks available through Buswell.
Another ebook source. Example search strategy: "east germany" OR "east german" AND sports OR athletics
Below are direct links to some of the pertinent subject-specific databases for the range of topics you've chosen.
Linking Google Scholar to the library's resources via "Find it @ Wheaton":
Expressing your research topic in the following framework will help you arrive at a clear research question:
Source: Booth, Wayne C., Gregory G. Colomb, and Joseph M. Williams. The Craft of Research. University of Chicago Press, 2008, p. 46.
~With your thesis, you need to take a stance, but you can take that stance only after you have considered the evidence~