@article{MAN_1978__237_182792,
     author = {Jens Peter Reuss Christensen},
     title = {The {Small} {Ball} {Theorem} for {Hilbert} {Spaces.}},
     journal = {Mathematische Annalen},
     pages = {273--276},
     publisher = {mathdoc},
     volume = {237},
     year = {1978},
     zbl = {0368.28009},
     url = {http://geodesic.mathdoc.fr/item/MAN_1978__237_182792/}
}