whom vs whose

whom

pron
  • The person(s) whom; whomever. 

  • As the object of a verb. 

  • As the object of a preposition. 

  • Used to refer to a previously mentioned person or people. 

whose

pron
  • That or those of whom or belonging to whom. 

det
  • Of whom, belonging to whom; which person's or people's. 

  • Of which, belonging to which. 

  • Of whom, belonging to whom. 

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