area of authority vs fu

area of authority

noun
  • the extent of someone's expertise, authority, activity or knowledge 

fu

noun
  • Expertise, mastery 

  • A Chinese literary form developed during the times of the Han dynasty that combines prose and poetry, sometimes called rhymed prose. 

  • flux unit 

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