@article{JRAM_1984__346_152592,
     author = {O. Bratteli and G. A. Elliott and P. E. T. Jorgensen},
     title = {Decomposition of unbounded derivations into invariant and approximately inner parts.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {166--193},
     publisher = {mathdoc},
     volume = {346},
     year = {1984},
     zbl = {0515.46057},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1984__346_152592/}
}