@article{MS2_1959__7_165712,
     author = {Lars H\"ormander},
     title = {On the {Uniqueness} of the {Cauchy} {Problem} {II.}},
     journal = {Mathematica Scandinavica},
     pages = {177--190},
     publisher = {mathdoc},
     volume = {7},
     year = {1959},
     zbl = {0090.08001},
     url = {http://geodesic.mathdoc.fr/item/MS2_1959__7_165712/}
}