New rules for theses have been in force since the summer semester 2012.
Please visit the PMT server https://pmt.hdm-stuttgart.de/downloads for information.
There are various ways of citing sources and references in theses or academic papers. The so-called Harvard style (named after the famous Harvard University) is very common and recommended. The Harvard style guide can be found at http://libweb.anglia.ac.uk/referencing/harvard.htm.
G. Hübner