@article{PORMA_1956__15_2_114767,
     author = {Silveira, M. da},
     title = {General operational calculus in n variables},
     journal = {Portugaliae mathematica},
     pages = {49--69},
     year = {1956},
     volume = {15},
     number = {2},
     mrnumber = {0083693},
     zbl = {0074.09604},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1956__15_2_114767/}
}