@article{700811,
     title = {On norms and subsets of linear spaces},
     booktitle = {General Topology and its Relations to Modern Analysis and Algebra},
     series = {GDML\_Books},
     publisher = {Academia Publishing House of the Czechoslovak Academy of Sciences},
     address = {Praha},
     year = {1972},
     pages = {97-97},
     mrnumber = {MR0301485},
     zbl = {0225.46019},
     url = {http://dml.mathdoc.fr/item/700811}
}

Daneš, J. On norms and subsets of linear spaces, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books,  (1972), p. 97. http://gdmltest.u-ga.fr/item/700811/