https://books.google.fr/books?id=RdTQCmXcNKYC&printsec=frontcover&dq=Jean-Claude+Cheynet&hl=fr&sa=X&ei=TW-QVPmpKI_TaPXhgbgD&ved=0CEUQ6AEwBA#v=onepage&q=Jean-Claude%20Cheynet&f=false
https://books.google.fr/books?id=vicqWvzRLkYC&printsec=frontcover&dq=Jean-Claude+Cheynet&hl=fr&sa=X&ei=TW-QVPmpKI_TaPXhgbgD&ved=0CC4Q6AEwAA#v=onepage&q=Jean-Claude%20Cheynet&f=false
https://books.google.fr/books?id=vicqWvzRLkYC&printsec=frontcover&dq=Jean-Claude+Cheynet&hl=fr&sa=X&ei=TW-QVPmpKI_TaPXhgbgD&ved=0CC4Q6AEwAA#v=onepage&q=Jean-Claude%20Cheynet&f=false