cite vs invoke

cite

verb
  • to summon officially or authoritatively to appear in court. 

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

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

noun
  • a citation 

invoke

verb
  • To appeal for validation to a (notably cited) authority. 

  • To cause (a program or subroutine) to execute. 

  • To solicit, petition for, appeal to a favorable attitude. 

  • To conjure up with incantations. 

  • To call to mind (something) for some purpose. 

  • To bring about as an inevitable consequence. 

  • To call upon (a person, a god) for help, assistance or guidance. 

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