Among her students was Silke Rottenberg .
From 1968 to 2007 , Christel Frese worked as a teacher of sports , mathematics and biology at the Marienschule .
Among Christel Frese 's students was Silke Rottenberg .
From 1968 to 2007 , Christel Frese worked as a teacher of sports , mathematics and biology at the Marienschule .