@article{JOLT_1991_1_2_a11,
     author = {J. Friedrich},
     title = { Extension of {Positive} {Definite} {Functions} on {Lie} {Groups}},
     journal = {Journal of Lie Theory},
     pages = {225--234},
     year = {1991},
     volume = {1},
     number = {2},
     zbl = {0762.43004},
     url = {http://geodesic.mathdoc.fr/item/JOLT_1991_1_2_a11/}
}