@article{MS2_1981__49_166771,
     author = {Peter Sj\"ogren},
     title = {Characterisations of {Poisson} integrals on symmetric spaces.},
     journal = {Mathematica Scandinavica},
     pages = {229--249},
     publisher = {mathdoc},
     volume = {49},
     year = {1981},
     zbl = {0464.53041},
     url = {http://geodesic.mathdoc.fr/item/MS2_1981__49_166771/}
}