question: return me the paper after 2000 in VLDB conference with more than 200 citations . 
#1 return VLDB conferences 
#2 return papers of #1 
#3 return #2 that are after 2000 
#4 return citations of #3 
#5 return number of  #4 for each #3 
#6 return #3 where #5 is more than 200