@article{MAN_1967__172_161582,
     author = {E. Spiegel},
     title = {On the {Structure} of the {Infinite} {Dimensional} {Unitary} {Group}},
     journal = {Mathematische Annalen},
     pages = {197--202},
     publisher = {mathdoc},
     volume = {172},
     year = {1967},
     zbl = {0146.25506},
     url = {http://geodesic.mathdoc.fr/item/MAN_1967__172_161582/}
}