@article{RM_1971_26_2_a7,
     author = {H. Lewy},
     title = {Generalization of a~theorem on the spatial angle},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {131--137},
     publisher = {mathdoc},
     volume = {26},
     number = {2},
     year = {1971},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1971_26_2_a7/}
}