read up vs revise

read up

verb
  • To learn (about something) by reading. 

revise

verb
  • To look over again (something previously written or learned), especially in preparation for an examination. 

  • To review, alter and amend, especially of written material. 

noun
  • A second proof sheet; a proof sheet taken after the first or a subsequent correction. 

  • A review or a revision. 

How often have the words read up and revise occurred in a corpus of books? (source: Google Ngram Viewer )