@article{MM2_1977__23_154508,
     author = {Herbert Gross and Hans A. Keller},
     title = {On the {Definition} of {Hilbert} {Space.}},
     journal = {Manuscripta mathematica},
     pages = {67--90},
     year = {1977},
     volume = {23},
     zbl = {0365.46023},
     url = {http://geodesic.mathdoc.fr/item/MM2_1977__23_154508/}
}