@article{MZ_1968__108_171117,
     author = {Werner Krabs},
     title = {Asymptotische {Konvexit\"at} bei der {Approximation} in normierten {Vektorr\"aumen.}},
     journal = {Mathematische Zeitschrift},
     pages = {368--376},
     publisher = {mathdoc},
     volume = {108},
     year = {1968},
     zbl = {0193.41002},
     url = {http://geodesic.mathdoc.fr/item/MZ_1968__108_171117/}
}