sit-down vs work-to-rule

sit-down

noun
  • A sit-in, a protest of civil disobedience by people sitting and refusing to move. 

  • An act of sitting down, especially with other people in some form of social exchange. 

adj
  • Intended to be done, used, consumed etc. while sitting. 

work-to-rule

noun
  • A labor protest in which employees do only the minimum work required by the rules of a workplace, following safety or other regulations to the letter in order to cause a slowdown. 

adj
  • Of or pertaining to such a protest. 

How often have the words sit-down and work-to-rule occurred in a corpus of books? (source: Google Ngram Viewer )