@article{whittaker:1903:fap,
    author = {Whittaker, E. T.},
     title = {On the functions associated with the parabolic cylinder
             in harmonic analysis},
   journal = {Proc. London Math. Soc.},
      year = {1902},
    volume = {35},
     pages = {417–427},
       doi = {10.1112/plms/s1-35.1.417},
     zblno = {34.0520.01}}