@article{MS2_1976__39_166506,
     author = {Lars Vretare},
     title = {Elementary spherical functions on symmetric spaces.},
     journal = {Mathematica Scandinavica},
     pages = {343--358},
     publisher = {mathdoc},
     volume = {39},
     year = {1976},
     zbl = {0387.43009},
     url = {http://geodesic.mathdoc.fr/item/MS2_1976__39_166506/}
}