return me the author in the " University of Michigan " whose papers have the most total citations . 
return authors ;return papers of  #1 ;return #2 where #1 is  in the  University of  Michigan ;return citations of  #3 ;return sum of  #4 for each  #3 ;return #1 where #5 is  highest
['select', 'project', 'comparative', 'project', 'group', 'superlative']