@article{MS2_1980__47_166718,
     author = {Magnus B. Landstad},
     title = {Algebras of spherical functions associated with covariant systems over a compact group.},
     journal = {Mathematica Scandinavica},
     pages = {137--149},
     publisher = {mathdoc},
     volume = {47},
     year = {1980},
     zbl = {0444.46050},
     url = {http://geodesic.mathdoc.fr/item/MS2_1980__47_166718/}
}