@article{MS2_1973__32_166297,
     author = {V\'aclav Zizler},
     title = {On {Some} {Extremal} {Problems} in {Banach} {Spaces.}},
     journal = {Mathematica Scandinavica},
     pages = {214--224},
     publisher = {mathdoc},
     volume = {32},
     year = {1973},
     zbl = {0269.46014},
     url = {http://geodesic.mathdoc.fr/item/MS2_1973__32_166297/}
}