@article{heckman:1991:eah,
    author = {Heckman, G. J.},
     title = {An elementary approach to the hypergeometric shift operators
              of {O}pdam},
   journal = {Invent. Math.},
  fjournal = {Inventiones Mathematicae},
    volume = {103},
      year = {1991},
    number = {2},
     pages = {341–350},
      issn = {0020-9910},
     coden = {INVMBH},
   mrclass = {33C80},
  mrnumber = {MR1085111 (92i:33012)},
mrreviewer = {Eric M. Opdam},
       doi = {10.1007/BF01239517},
     zblno = {0721.33009}}