@article{BSMF_2002__130_3_337_0,
     author = {Azagra, Daniel and Jim\'enez-Sevilla, Mar},
     title = {On the size of the sets of gradients of bump functions and starlike bodies on the {Hilbert} space},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {337--347},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {130},
     number = {3},
     year = {2002},
     doi = {10.24033/bsmf.2422},
     mrnumber = {1943881},
     zbl = {1034.46016},
     language = {en},
     url = {http://www.numdam.org/articles/10.24033/bsmf.2422/}
}