@article{koornwinder:1975:jpa,
    author = {Koornwinder, Tom H.},
     title = {{J}acobi polynomials. {I}{I}{I}. {A}n analytic proof of the
              addition formula},
   journal = {SIAM. J. Math. Anal.},
    volume = {6},
      year = {1975},
     pages = {533–543},
   mrclass = {33A65},
  mrnumber = {MR0447659 (56 \#5969)},
mrreviewer = {G. Gasper},
       doi = {10.1137/0506048},
     zblno = {0299.33012}}