power source vs works

power source

noun
  • A source of power such as a generator or mains outlet. 

works

noun
  • A mechanism or machine; the means by which something happens. 

  • A drug addict's equipment: syringe, needle, etc. 

  • Everything or everything that is available or possible; especially, all available toppings on food. 

  • Drastic treatment; abuse; the axe (dismissal). 

  • A factory or factories, or similar collection(s) of buildings. 

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