@article{MS2_1962__10_165803,
     author = {Egil A. Hylleraas},
     title = {Linearization of {Products} of {Jacobi} {Polynomials.}},
     journal = {Mathematica Scandinavica},
     pages = {189--200},
     publisher = {mathdoc},
     volume = {10},
     year = {1962},
     zbl = {0109.29603},
     url = {http://geodesic.mathdoc.fr/item/MS2_1962__10_165803/}
}