@article{AM2_1992__44_1_137497,
     author = {Zbigniew Gajda},
     title = {On trigonometric polynomials spanned by characters of unitary representations.},
     journal = {Aequationes mathematicae},
     pages = {259--277},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1992},
     zbl = {0765.39007},
     url = {http://geodesic.mathdoc.fr/item/AM2_1992__44_1_137497/}
}