cite vs sift out

cite

verb
  • to list the source(s) from which one took information, words or literary or verbal context. 

  • to quote; to repeat, as a passage from a book, or the words of another. 

  • to summon officially or authoritatively to appear in court. 

noun
  • a citation 

sift out

verb
  • To isolate or identify one particular thing from a collection that includes less relevant things. 

How often have the words cite and sift out occurred in a corpus of books? (source: Google Ngram Viewer )