@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}}