@article{MS2_1964__15_165892,
     author = {J. Peetre},
     title = {Remark on {Eigenfunction} {Expansions} for {Elliptic} {Operators} with {Constant} {Coefficients.}},
     journal = {Mathematica Scandinavica},
     pages = {83--92},
     publisher = {mathdoc},
     volume = {15},
     year = {1964},
     zbl = {0131.09802},
     url = {http://geodesic.mathdoc.fr/item/MS2_1964__15_165892/}
}