calling card vs papers

calling card

noun
  • A phonecard. 

  • A card advertising the services of a prostitute. 

  • Excrement, especially of a domestic animal. 

  • A small printed card which identifies the bearer, traditionally presented for introduction when making a social visit to a home or when attending a formal social event or business meeting. 

  • An attribute, symptom, object, or behavior which is distinctly characteristic of someone or something. 

papers

noun
  • Official documents or identification, as a passport. 

  • cigarette papers 

  • A collection of documents, unpublished writing or correspondence in an archive or library collection. 

  • He lost his papers while travelling and had a hard time getting home. 

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