Pribiag, V.S., Krivorotov, I.N., Fuchs, G.D., Braganca, P.M., Özatay, Ö., Sankey, J.C., Ralph, D.C., Buhrman, R.A., “Magnetic Vortex Oscillator Driven by Dc Spin-Polarized Current”, Nature Physics, 1, 498-503, 2007.