F. Dolde, H. Fedder, M.W. Doherty, T. Noebauer, F. Rempp, G. Balasubramanian, T. Wolf, F. Reinhard, L.C.L. Hollenberg, F. Jelezko, J. Wrachtrup
NATURE PHYSICS Volume: 7 Issue: 6 Pages: 459-463 DOI: 10.1038/NPHYS1969
http://www.nature.com/nphys/journal/v7/n6/full/nphys1969.html