@article{humbert:1920:hyp,
    author = {Humbert, Pierre},
     title = {Sur les fonctions hypercylindriques},
   journal = {C. R. Acad. Sci. Paris S\'er. I Math.},
  fjournal = {Comptes Rendus de l'Acad\'emie des Sciences. S\'erie I.
              Math\'ematique},
    volume = {171},
      year = {1920},
     pages = {490–492},
  language = {French},
     zblno = {47.0348.02}}