@article{MS2_1961__9_165773,
     author = {Lars H\"ormander},
     title = {Hypoelliptic {Convolution} {Equations.}},
     journal = {Mathematica Scandinavica},
     pages = {178--184},
     publisher = {mathdoc},
     volume = {9},
     year = {1961},
     zbl = {0102.11003},
     url = {http://geodesic.mathdoc.fr/item/MS2_1961__9_165773/}
}