@article{JRAM_1988__384_152999,
     author = {Harald Upmeier},
     title = {Index theory for multivariable {Wiener-Hopf} operators.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {57--79},
     year = {1988},
     volume = {384},
     zbl = {0628.47018},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1988__384_152999/}
}