recension vs rectifying

recension

noun
  • A family of manuscripts which share similar traits; the variety of a language which is used in such manuscripts. 

  • A critical revision of a text. 

  • A census, an enumeration, a review, a survey. 

  • A text established by critical revision. 

rectifying

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