Complex sentence: According to a 2013 Oxford University study, the article on Croatia was the most disputed article on the German Wikipedia, while the ten most disputed articles of that Wikipedia also included Adolf Hitler, Scientology, and Rudolf Steiner.
Split into simpler sentences: According to a 2013 Oxford University study, the article on Croatia was the most disputed article on the German Wikipedia. The top ten most disputed articles also included Adolf Hitler, Scientology, and Rudolf Steiner.