return me the author in the " University of Michigan " in Databases area whose papers have more than 5000 total citations . 
return authors ;return #1 in the  University of Michigan ;return #2 in Databases areas ;return papers of #3 ;return citations of #4 ;return the  number of  #5 ;return #3 where #6 is  more than  5000
['select', 'filter', 'filter', 'project', 'project', 'aggregate', 'comparative']