@article{AM2_1990__40_1_137379,
     author = {K.J. Heuvers},
     title = {A characterization of {Cauchy} kernels.},
     journal = {Aequationes mathematicae},
     pages = {281--306},
     publisher = {mathdoc},
     volume = {40},
     number = {1},
     year = {1990},
     zbl = {0716.39004},
     url = {http://geodesic.mathdoc.fr/item/AM2_1990__40_1_137379/}
}