"Should someone come up with the idea that a member of my office may have collaborated on the academic preparation of my dissertation, I would have to answer - it's simply not true, " said Mr Guttenberg.

BBC: German minister denies plagiarism on PhD thesis

Professor Barbara Zehnpfennig, whose newspaper article was allegedly used in the opening of the dissertation, told German news channel N24 that failing to credit another author "breaks all academic rules".

BBC: German minister denies plagiarism on PhD thesis