@article{IM_1978__45_142548,
     author = {Gert K. Petersen},
     title = {Approximating {Derivations} on {Ideals} of {C*-Algebras.}},
     journal = {Inventiones mathematicae},
     pages = {299--305},
     publisher = {mathdoc},
     volume = {45},
     year = {1978},
     zbl = {0376.46040},
     url = {http://geodesic.mathdoc.fr/item/IM_1978__45_142548/}
}