@article{MAN_1980__250_163409,
     author = {Klaus Saatkamp},
     title = {Best {Approximation} in the {Space} of {Bounded} {Operators} and its {Applications.}},
     journal = {Mathematische Annalen},
     pages = {35--54},
     publisher = {mathdoc},
     volume = {250},
     year = {1980},
     zbl = {0419.41028},
     url = {http://geodesic.mathdoc.fr/item/MAN_1980__250_163409/}
}