@InCollection{Roy:1959,
  author =       {Bernard Roy},
  title =        {Transitivité et connexité},
  booktitle =    {Extrait des comptes rendus des séances de l’Académie des Sciences},
  publisher = {Gauthier-Villars},
  year =      1959,
  pages =     {216-218},
  month =     {July},
  note =      {\url{http://gallica.bnf.fr/ark:/12148/bpt6k3201c/f222.image.langFR}}
}
