@article{IM_1972__17_142164,
     author = {A. Hulanicki},
     title = {On the {Spectrum} of {Convolution} {Operators} on {Groups} with {Polynomial} {Growth.}},
     journal = {Inventiones mathematicae},
     pages = {135--142},
     year = {1972},
     volume = {17},
     zbl = {0264.43007},
     url = {http://geodesic.mathdoc.fr/item/IM_1972__17_142164/}
}